diff --git a/app/controllers/fuel_entries_controller.rb b/app/controllers/fuel_entries_controller.rb
index db6b5f5..db1fc07 100644
--- a/app/controllers/fuel_entries_controller.rb
+++ b/app/controllers/fuel_entries_controller.rb
@@ -38,9 +38,20 @@ class FuelEntriesController < ApplicationController
   end
 
   def prepare_vehicle_show
-    @maintenance_schedules = @vehicle.maintenance_schedules.order(:maintenance_type)
+    @maintenance_schedules = @vehicle.maintenance_schedules.active.order(:maintenance_type)
+    @maintenance_schedule_statuses = maintenance_schedule_statuses(@maintenance_schedules)
     @fuel_entries = @vehicle.fuel_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @maintenance_entries = @vehicle.maintenance_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @maintenance_entry = @vehicle.maintenance_entries.build(date: Date.current)
   end
+
+  def maintenance_schedule_statuses(schedules)
+    schedules.index_with do |schedule|
+      latest_entry = @vehicle.maintenance_entries
+        .where("lower(name) = ?", schedule.maintenance_type.downcase)
+        .order(date: :desc, created_at: :desc)
+        .first
+      MaintenanceScheduleStatus.new(schedule, latest_entry, current_odometer: @vehicle.current_odometer)
+    end
+  end
 end
diff --git a/app/controllers/maintenance_entries_controller.rb b/app/controllers/maintenance_entries_controller.rb
index be23e21..e614be5 100644
--- a/app/controllers/maintenance_entries_controller.rb
+++ b/app/controllers/maintenance_entries_controller.rb
@@ -53,9 +53,20 @@ class MaintenanceEntriesController < ApplicationController
   end
 
   def prepare_vehicle_show
-    @maintenance_schedules = @vehicle.maintenance_schedules.order(:maintenance_type)
+    @maintenance_schedules = @vehicle.maintenance_schedules.active.order(:maintenance_type)
+    @maintenance_schedule_statuses = maintenance_schedule_statuses(@maintenance_schedules)
     @fuel_entries = @vehicle.fuel_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @maintenance_entries = @vehicle.maintenance_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @fuel_entry = @vehicle.fuel_entries.build(date: Date.current)
   end
+
+  def maintenance_schedule_statuses(schedules)
+    schedules.index_with do |schedule|
+      latest_entry = @vehicle.maintenance_entries
+        .where("lower(name) = ?", schedule.maintenance_type.downcase)
+        .order(date: :desc, created_at: :desc)
+        .first
+      MaintenanceScheduleStatus.new(schedule, latest_entry, current_odometer: @vehicle.current_odometer)
+    end
+  end
 end
diff --git a/app/controllers/maintenance_schedules_controller.rb b/app/controllers/maintenance_schedules_controller.rb
new file mode 100644
index 0000000..357294e
--- /dev/null
+++ b/app/controllers/maintenance_schedules_controller.rb
@@ -0,0 +1,65 @@
+class MaintenanceSchedulesController < ApplicationController
+  before_action :set_vehicle
+  before_action :set_maintenance_schedule, only: %i[show edit update deactivate]
+
+  def index
+    @maintenance_schedules = @vehicle.maintenance_schedules.order(active: :desc, maintenance_type: :asc)
+  end
+
+  def show
+  end
+
+  def new
+    @maintenance_schedule = @vehicle.maintenance_schedules.build(
+      baseline_odometer: @vehicle.current_odometer,
+      baseline_date: Date.current
+    )
+  end
+
+  def create
+    @maintenance_schedule = @vehicle.maintenance_schedules.build(maintenance_schedule_params)
+
+    if @maintenance_schedule.save
+      redirect_to vehicle_maintenance_schedules_path(@vehicle), notice: "Maintenance schedule created."
+    else
+      render :new, status: :unprocessable_entity
+    end
+  end
+
+  def edit
+  end
+
+  def update
+    if @maintenance_schedule.update(maintenance_schedule_params)
+      redirect_to vehicle_maintenance_schedules_path(@vehicle), notice: "Maintenance schedule updated."
+    else
+      render :edit, status: :unprocessable_entity
+    end
+  end
+
+  def deactivate
+    @maintenance_schedule.update!(active: false)
+    redirect_to vehicle_maintenance_schedules_path(@vehicle), notice: "Maintenance schedule deactivated."
+  end
+
+  private
+
+  def set_vehicle
+    @vehicle = Vehicle.find(params[:vehicle_id])
+  end
+
+  def set_maintenance_schedule
+    @maintenance_schedule = @vehicle.maintenance_schedules.find(params[:id])
+  end
+
+  def maintenance_schedule_params
+    params.require(:maintenance_schedule).permit(
+      :maintenance_type,
+      :mileage_interval,
+      :time_interval,
+      :baseline_odometer,
+      :baseline_date,
+      :active
+    )
+  end
+end
diff --git a/app/controllers/vehicles_controller.rb b/app/controllers/vehicles_controller.rb
index ee2c705..7f57bd9 100644
--- a/app/controllers/vehicles_controller.rb
+++ b/app/controllers/vehicles_controller.rb
@@ -72,10 +72,27 @@ class VehiclesController < ApplicationController
   end
 
   def prepare_show
-    @maintenance_schedules = @vehicle.maintenance_schedules.order(:maintenance_type)
+    @maintenance_schedules = @vehicle.maintenance_schedules.active.order(:maintenance_type)
+    @maintenance_schedule_statuses = maintenance_schedule_statuses(@maintenance_schedules)
     @fuel_entries = @vehicle.fuel_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @maintenance_entries = @vehicle.maintenance_entries.includes(:updated_by_user).order(date: :desc, created_at: :desc)
     @fuel_entry ||= @vehicle.fuel_entries.build(date: Date.current)
     @maintenance_entry ||= @vehicle.maintenance_entries.build(date: Date.current)
   end
+
+  def maintenance_schedule_statuses(schedules)
+    schedules.index_with do |schedule|
+      latest_entry = latest_maintenance_entry_for(schedule)
+      status = MaintenanceScheduleStatus.new(schedule, latest_entry, current_odometer: @vehicle.current_odometer)
+      MaintenanceNotification.record_status_change(schedule, status)
+      status
+    end
+  end
+
+  def latest_maintenance_entry_for(schedule)
+    @vehicle.maintenance_entries
+      .where("lower(name) = ?", schedule.maintenance_type.downcase)
+      .order(date: :desc, created_at: :desc)
+      .first
+  end
 end
diff --git a/app/models/maintenance_entry.rb b/app/models/maintenance_entry.rb
index 62632b8..3a1133e 100644
--- a/app/models/maintenance_entry.rb
+++ b/app/models/maintenance_entry.rb
@@ -20,9 +20,9 @@ class MaintenanceEntry < ApplicationRecord
     return if vehicle.blank? || name.blank?
 
     scheduled = vehicle.maintenance_schedules.any? do |schedule|
-      schedule.maintenance_type.casecmp?(name)
+      schedule.active? && schedule.maintenance_type.casecmp?(name)
     end
-    scheduled ||= vehicle.maintenance_schedules.where("lower(maintenance_type) = ?", name.downcase).exists? if vehicle.persisted?
+    scheduled ||= vehicle.maintenance_schedules.active.where("lower(maintenance_type) = ?", name.downcase).exists? if vehicle.persisted?
     return if scheduled
 
     errors.add(:name, "must match a maintenance schedule for the vehicle")
diff --git a/app/models/maintenance_notification.rb b/app/models/maintenance_notification.rb
new file mode 100644
index 0000000..5ffa722
--- /dev/null
+++ b/app/models/maintenance_notification.rb
@@ -0,0 +1,18 @@
+class MaintenanceNotification
+  NOTIFIABLE_STATUSES = %w[upcoming overdue].freeze
+
+  def self.record_status_change(schedule, status)
+    return if schedule.last_status == status.status
+
+    previous_status = schedule.last_status.presence || "unknown"
+    schedule.update!(last_status: status.status, last_status_changed_at: Time.current)
+    return unless NOTIFIABLE_STATUSES.include?(status.status)
+
+    Rails.logger.warn(
+      "Maintenance schedule #{status.status}: vehicle_id=#{schedule.vehicle_id} " \
+        "maintenance_schedule_id=#{schedule.id} maintenance_type=#{schedule.maintenance_type.inspect} " \
+        "previous_status=#{previous_status} due_odometer=#{status.due_odometer} due_date=#{status.due_date} " \
+        "reason=#{status.reason.inspect}"
+    )
+  end
+end
diff --git a/app/models/maintenance_schedule.rb b/app/models/maintenance_schedule.rb
index 467c801..fe677f6 100644
--- a/app/models/maintenance_schedule.rb
+++ b/app/models/maintenance_schedule.rb
@@ -4,4 +4,18 @@ class MaintenanceSchedule < ApplicationRecord
   validates :maintenance_type, presence: true, uniqueness: { scope: :vehicle_id, case_sensitive: false }
   validates :mileage_interval, presence: true, numericality: { only_integer: true, greater_than: 0 }
   validates :time_interval, presence: true, numericality: { only_integer: true, greater_than: 0 }
+  validates :baseline_odometer, presence: true, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :baseline_date, presence: true
+  validates :active, inclusion: { in: [ true, false ] }
+  validate :baseline_date_cannot_be_in_the_future
+
+  scope :active, -> { where(active: true) }
+
+  private
+
+  def baseline_date_cannot_be_in_the_future
+    return if baseline_date.blank? || baseline_date <= Date.current
+
+    errors.add(:baseline_date, "can't be in the future")
+  end
 end
diff --git a/app/models/maintenance_schedule_status.rb b/app/models/maintenance_schedule_status.rb
new file mode 100644
index 0000000..173a822
--- /dev/null
+++ b/app/models/maintenance_schedule_status.rb
@@ -0,0 +1,110 @@
+class MaintenanceScheduleStatus
+  UPCOMING_PERCENT = 0.05
+
+  attr_reader :schedule, :latest_entry, :status, :due_odometer, :due_date
+
+  def initialize(schedule, latest_entry, current_odometer:)
+    @schedule = schedule
+    @latest_entry = latest_entry
+    @current_odometer = current_odometer
+    @due_odometer = baseline_odometer + schedule.mileage_interval
+    @due_date = baseline_date + schedule.time_interval.days
+    @status = calculate_status
+  end
+
+  def overdue?
+    status == "overdue"
+  end
+
+  def upcoming?
+    status == "upcoming"
+  end
+
+  def no_history?
+    status == "no_history"
+  end
+
+  def current?
+    status == "current"
+  end
+
+  def status_label
+    case status
+    when "overdue" then "Overdue"
+    when "upcoming" then "Upcoming"
+    when "no_history" then "No history"
+    else "Current"
+    end
+  end
+
+  def reason
+    case status
+    when "overdue"
+      overdue_reasons.join(" and ")
+    when "upcoming"
+      upcoming_reasons.join(" and ")
+    when "no_history"
+      "No matching maintenance entry has been recorded."
+    else
+      "Maintenance is current."
+    end
+  end
+
+  private
+
+  attr_reader :current_odometer
+
+  def calculate_status
+    return "overdue" if mileage_overdue? || time_overdue?
+    return "upcoming" if mileage_upcoming? || time_upcoming?
+    return "no_history" if latest_entry.blank?
+
+    "current"
+  end
+
+  def baseline_odometer
+    latest_entry&.odometer || schedule.baseline_odometer
+  end
+
+  def baseline_date
+    latest_entry&.date || schedule.baseline_date
+  end
+
+  def mileage_overdue?
+    current_odometer >= due_odometer
+  end
+
+  def time_overdue?
+    Date.current >= due_date
+  end
+
+  def mileage_upcoming?
+    current_odometer >= due_odometer - mileage_upcoming_window
+  end
+
+  def time_upcoming?
+    Date.current >= due_date - time_upcoming_window.days
+  end
+
+  def mileage_upcoming_window
+    (schedule.mileage_interval * UPCOMING_PERCENT).ceil
+  end
+
+  def time_upcoming_window
+    (schedule.time_interval * UPCOMING_PERCENT).ceil
+  end
+
+  def overdue_reasons
+    reasons = []
+    reasons << "mileage interval reached" if mileage_overdue?
+    reasons << "time interval reached" if time_overdue?
+    reasons
+  end
+
+  def upcoming_reasons
+    reasons = []
+    reasons << "within #{mileage_upcoming_window} miles of due odometer" if mileage_upcoming?
+    reasons << "within #{time_upcoming_window} days of due date" if time_upcoming?
+    reasons
+  end
+end
diff --git a/app/views/maintenance_schedules/_form.html.erb b/app/views/maintenance_schedules/_form.html.erb
new file mode 100644
index 0000000..5de17b0
--- /dev/null
+++ b/app/views/maintenance_schedules/_form.html.erb
@@ -0,0 +1,47 @@
+<%= form_with model: [vehicle, maintenance_schedule] do |form| %>
+  <% if maintenance_schedule.errors.any? %>
+    <section>
+      <h2><%= pluralize(maintenance_schedule.errors.count, "error") %> prevented this maintenance schedule from being saved</h2>
+
+      <ul>
+        <% maintenance_schedule.errors.full_messages.each do |message| %>
+          <li><%= message %></li>
+        <% end %>
+      </ul>
+    </section>
+  <% end %>
+
+  <div>
+    <%= form.label :maintenance_type %><br>
+    <%= form.text_field :maintenance_type, required: true %>
+  </div>
+
+  <div>
+    <%= form.label :mileage_interval %><br>
+    <%= form.number_field :mileage_interval, min: 1, required: true %>
+  </div>
+
+  <div>
+    <%= form.label :time_interval, "Time interval in days" %><br>
+    <%= form.number_field :time_interval, min: 1, required: true %>
+  </div>
+
+  <div>
+    <%= form.label :baseline_odometer %><br>
+    <%= form.number_field :baseline_odometer, min: 0, required: true %>
+  </div>
+
+  <div>
+    <%= form.label :baseline_date %><br>
+    <%= form.date_field :baseline_date, max: Date.current, required: true %>
+  </div>
+
+  <div>
+    <%= form.check_box :active %>
+    <%= form.label :active %>
+  </div>
+
+  <div>
+    <%= form.submit %>
+  </div>
+<% end %>
diff --git a/app/views/maintenance_schedules/edit.html.erb b/app/views/maintenance_schedules/edit.html.erb
new file mode 100644
index 0000000..356eb98
--- /dev/null
+++ b/app/views/maintenance_schedules/edit.html.erb
@@ -0,0 +1,7 @@
+<main>
+  <p><%= link_to "Back to maintenance schedules", vehicle_maintenance_schedules_path(@vehicle) %></p>
+
+  <h1>Edit Maintenance Schedule</h1>
+
+  <%= render "form", vehicle: @vehicle, maintenance_schedule: @maintenance_schedule %>
+</main>
diff --git a/app/views/maintenance_schedules/index.html.erb b/app/views/maintenance_schedules/index.html.erb
new file mode 100644
index 0000000..2f56b49
--- /dev/null
+++ b/app/views/maintenance_schedules/index.html.erb
@@ -0,0 +1,46 @@
+<main>
+  <p><%= notice %></p>
+
+  <p><%= link_to "Back to vehicle", vehicle_path(@vehicle) %></p>
+
+  <h1>Maintenance Schedules</h1>
+  <p><%= @vehicle.year %> <%= @vehicle.make %> <%= @vehicle.model %></p>
+
+  <p><%= link_to "New maintenance schedule", new_vehicle_maintenance_schedule_path(@vehicle) %></p>
+
+  <% if @maintenance_schedules.any? %>
+    <table>
+      <thead>
+        <tr>
+          <th>Type</th>
+          <th>Mileage interval</th>
+          <th>Time interval</th>
+          <th>Baseline odometer</th>
+          <th>Baseline date</th>
+          <th>Status</th>
+          <th>Actions</th>
+        </tr>
+      </thead>
+      <tbody>
+        <% @maintenance_schedules.each do |schedule| %>
+          <tr>
+            <td><%= link_to schedule.maintenance_type, vehicle_maintenance_schedule_path(@vehicle, schedule) %></td>
+            <td><%= number_with_delimiter(schedule.mileage_interval) %> miles</td>
+            <td><%= schedule.time_interval %> days</td>
+            <td><%= number_with_delimiter(schedule.baseline_odometer) %></td>
+            <td><%= schedule.baseline_date %></td>
+            <td><%= schedule.active? ? "Active" : "Inactive" %></td>
+            <td>
+              <%= link_to "Edit", edit_vehicle_maintenance_schedule_path(@vehicle, schedule) %>
+              <% if schedule.active? %>
+                <%= button_to "Deactivate", deactivate_vehicle_maintenance_schedule_path(@vehicle, schedule), method: :patch %>
+              <% end %>
+            </td>
+          </tr>
+        <% end %>
+      </tbody>
+    </table>
+  <% else %>
+    <p>No maintenance schedules recorded.</p>
+  <% end %>
+</main>
diff --git a/app/views/maintenance_schedules/new.html.erb b/app/views/maintenance_schedules/new.html.erb
new file mode 100644
index 0000000..3ca2a5d
--- /dev/null
+++ b/app/views/maintenance_schedules/new.html.erb
@@ -0,0 +1,7 @@
+<main>
+  <p><%= link_to "Back to maintenance schedules", vehicle_maintenance_schedules_path(@vehicle) %></p>
+
+  <h1>New Maintenance Schedule</h1>
+
+  <%= render "form", vehicle: @vehicle, maintenance_schedule: @maintenance_schedule %>
+</main>
diff --git a/app/views/maintenance_schedules/show.html.erb b/app/views/maintenance_schedules/show.html.erb
new file mode 100644
index 0000000..d47c469
--- /dev/null
+++ b/app/views/maintenance_schedules/show.html.erb
@@ -0,0 +1,26 @@
+<main>
+  <p><%= notice %></p>
+
+  <p><%= link_to "Back to maintenance schedules", vehicle_maintenance_schedules_path(@vehicle) %></p>
+
+  <h1><%= @maintenance_schedule.maintenance_type %></h1>
+
+  <dl>
+    <dt>Mileage interval</dt>
+    <dd><%= number_with_delimiter(@maintenance_schedule.mileage_interval) %> miles</dd>
+
+    <dt>Time interval</dt>
+    <dd><%= @maintenance_schedule.time_interval %> days</dd>
+
+    <dt>Baseline odometer</dt>
+    <dd><%= number_with_delimiter(@maintenance_schedule.baseline_odometer) %></dd>
+
+    <dt>Baseline date</dt>
+    <dd><%= @maintenance_schedule.baseline_date %></dd>
+
+    <dt>Status</dt>
+    <dd><%= @maintenance_schedule.active? ? "Active" : "Inactive" %></dd>
+  </dl>
+
+  <p><%= link_to "Edit", edit_vehicle_maintenance_schedule_path(@vehicle, @maintenance_schedule) %></p>
+</main>
diff --git a/app/views/vehicles/show.html.erb b/app/views/vehicles/show.html.erb
index 21ee1dc..38169ec 100644
--- a/app/views/vehicles/show.html.erb
+++ b/app/views/vehicles/show.html.erb
@@ -49,6 +49,54 @@
   <section>
     <h2>Maintenance Schedules</h2>
 
+    <p><%= link_to "Manage maintenance schedules", vehicle_maintenance_schedules_path(@vehicle) %></p>
+
+    <% overdue_statuses = @maintenance_schedule_statuses.values.select(&:overdue?) %>
+    <% upcoming_statuses = @maintenance_schedule_statuses.values.select(&:upcoming?) %>
+    <% no_history_statuses = @maintenance_schedule_statuses.values.select(&:no_history?) %>
+
+    <% if overdue_statuses.any? %>
+      <section>
+        <h3>Overdue Maintenance</h3>
+        <ul>
+          <% overdue_statuses.each do |status| %>
+            <li>
+              <%= status.schedule.maintenance_type %> is overdue: <%= status.reason %>.
+              Due at <%= number_with_delimiter(status.due_odometer) %> miles or <%= status.due_date %>.
+            </li>
+          <% end %>
+        </ul>
+      </section>
+    <% end %>
+
+    <% if upcoming_statuses.any? %>
+      <section>
+        <h3>Upcoming Maintenance</h3>
+        <ul>
+          <% upcoming_statuses.each do |status| %>
+            <li>
+              <%= status.schedule.maintenance_type %> is upcoming: <%= status.reason %>.
+              Due at <%= number_with_delimiter(status.due_odometer) %> miles or <%= status.due_date %>.
+            </li>
+          <% end %>
+        </ul>
+      </section>
+    <% end %>
+
+    <% if no_history_statuses.any? %>
+      <section>
+        <h3>No Maintenance History</h3>
+        <ul>
+          <% no_history_statuses.each do |status| %>
+            <li>
+              <%= status.schedule.maintenance_type %> has no matching maintenance entry yet.
+              Baseline due point is <%= number_with_delimiter(status.due_odometer) %> miles or <%= status.due_date %>.
+            </li>
+          <% end %>
+        </ul>
+      </section>
+    <% end %>
+
     <% if @maintenance_schedules.any? %>
       <table>
         <thead>
@@ -56,14 +104,21 @@
             <th>Type</th>
             <th>Mileage interval</th>
             <th>Time interval</th>
+            <th>Next due odometer</th>
+            <th>Next due date</th>
+            <th>Status</th>
           </tr>
         </thead>
         <tbody>
           <% @maintenance_schedules.each do |schedule| %>
+            <% status = @maintenance_schedule_statuses.fetch(schedule) %>
             <tr>
               <td><%= schedule.maintenance_type %></td>
               <td><%= number_with_delimiter(schedule.mileage_interval) %> miles</td>
               <td><%= schedule.time_interval %> days</td>
+              <td><%= number_with_delimiter(status.due_odometer) %></td>
+              <td><%= status.due_date %></td>
+              <td><%= status.status_label %></td>
             </tr>
           <% end %>
         </tbody>
diff --git a/config/routes.rb b/config/routes.rb
index e346f47..bb4227c 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -16,6 +16,9 @@ Rails.application.routes.draw do
   resources :vehicles do
     resources :fuel_entries, only: :create
     resources :maintenance_entries, only: :create
+    resources :maintenance_schedules, except: :destroy do
+      patch :deactivate, on: :member
+    end
   end
 
   root "vehicles#index"
diff --git a/db/migrate/20260916120000_add_status_tracking_to_maintenance_schedules.rb b/db/migrate/20260916120000_add_status_tracking_to_maintenance_schedules.rb
new file mode 100644
index 0000000..98b43a9
--- /dev/null
+++ b/db/migrate/20260916120000_add_status_tracking_to_maintenance_schedules.rb
@@ -0,0 +1,30 @@
+class AddStatusTrackingToMaintenanceSchedules < ActiveRecord::Migration[8.1]
+  def change
+    add_column :maintenance_schedules, :baseline_odometer, :integer
+    add_column :maintenance_schedules, :baseline_date, :date
+    add_column :maintenance_schedules, :active, :boolean, default: true, null: false
+    add_column :maintenance_schedules, :last_status, :string
+    add_column :maintenance_schedules, :last_status_changed_at, :datetime
+
+    reversible do |dir|
+      dir.up do
+        execute <<~SQL.squish
+          UPDATE maintenance_schedules
+          SET baseline_odometer = (
+            SELECT vehicles.current_odometer
+            FROM vehicles
+            WHERE vehicles.id = maintenance_schedules.vehicle_id
+          )
+        SQL
+
+        execute <<~SQL.squish
+          UPDATE maintenance_schedules
+          SET baseline_date = DATE(created_at)
+        SQL
+      end
+    end
+
+    change_column_null :maintenance_schedules, :baseline_odometer, false
+    change_column_null :maintenance_schedules, :baseline_date, false
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 62027bd..dd0f49f 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_09_16_103647) do
+ActiveRecord::Schema[8.1].define(version: 2026_09_16_120000) do
   create_table "access_keys", force: :cascade do |t|
     t.boolean "auto_rotate", default: true, null: false
     t.integer "auto_rotation_frequency_days", default: 30, null: false
@@ -48,7 +48,12 @@ ActiveRecord::Schema[8.1].define(version: 2026_09_16_103647) do
   end
 
   create_table "maintenance_schedules", force: :cascade do |t|
+    t.boolean "active", default: true, null: false
+    t.date "baseline_date", null: false
+    t.integer "baseline_odometer", null: false
     t.datetime "created_at", null: false
+    t.string "last_status"
+    t.datetime "last_status_changed_at"
     t.string "maintenance_type", null: false
     t.integer "mileage_interval", null: false
     t.integer "time_interval", null: false
diff --git a/executions/phase006.md b/executions/phase006.md
new file mode 100644
index 0000000..d32927a
--- /dev/null
+++ b/executions/phase006.md
@@ -0,0 +1,39 @@
+# Phase 006 Execution
+
+## Scope
+- Added maintenance schedule management pages.
+- Added manual schedule baselines for mileage and time calculations.
+- Added overdue, upcoming, no-history, and current maintenance status calculations.
+- Added vehicle show alerts for overdue, upcoming, and no-history schedules.
+- Added logger-backed notification behavior for status changes.
+- Added specs for schedule CRUD and maintenance status behavior.
+
+## Changes
+- Added schedule fields for `baseline_odometer`, `baseline_date`, `active`, `last_status`, and `last_status_changed_at`.
+- Added validation for manual baselines and schedule active state.
+- Added nested maintenance schedule routes under vehicles.
+- Added `MaintenanceSchedulesController` with list, show, new, create, edit, update, and deactivate actions.
+- Added separate maintenance schedule views and a shared form partial.
+- Added `MaintenanceScheduleStatus` for calculating due odometer/date and status.
+- Added `MaintenanceNotification` as the isolated notification stub that logs status changes through `Rails.logger`.
+- Updated `vehicles#show` to show overdue alerts, upcoming warnings, no-history notices, next due odometer, next due date, and status.
+- Updated maintenance entry validation and forms to use only active schedules for new entries.
+- Added request specs for schedule CRUD, soft deactivation, vehicle alerts, and status-change logging.
+- Added model specs for mileage-based, time-based, upcoming, no-history, and current status cases.
+
+## Decisions
+- Maintenance schedule baselines are manually entered per schedule.
+- Without matching maintenance history, status uses the schedule baseline.
+- With matching maintenance history, status uses the latest matching maintenance entry instead of the schedule baseline.
+- A schedule is overdue exactly when either mileage or time interval is reached.
+- Upcoming warnings use a 5% lead window for both mileage and time intervals.
+- Schedules are soft-deactivated instead of deleted.
+- Vehicle show is allowed to update stored status tracking and log status changes.
+- Status changes are stored for all statuses, but notifications are logged only for `upcoming` and `overdue` statuses.
+
+## Verification
+- Passed: `bundle exec rspec spec/models/maintenance_schedule_spec.rb spec/models/maintenance_schedule_status_spec.rb`
+- Passed: `bundle exec rspec spec/requests/vehicles_spec.rb`
+- Passed: `bundle exec rspec`
+- Passed: `bin/rubocop app/models/maintenance_schedule.rb app/models/maintenance_entry.rb app/models/maintenance_schedule_status.rb app/models/maintenance_notification.rb app/controllers/vehicles_controller.rb app/controllers/fuel_entries_controller.rb app/controllers/maintenance_entries_controller.rb app/controllers/maintenance_schedules_controller.rb spec/models/maintenance_schedule_spec.rb spec/models/maintenance_schedule_status_spec.rb spec/requests/vehicles_spec.rb`
+- Passed: `bin/ci`
diff --git a/spec/factories/maintenance_schedules.rb b/spec/factories/maintenance_schedules.rb
index 7a40627..ed8ed77 100644
--- a/spec/factories/maintenance_schedules.rb
+++ b/spec/factories/maintenance_schedules.rb
@@ -4,5 +4,8 @@ FactoryBot.define do
     maintenance_type { "Oil Change" }
     mileage_interval { 5_000 }
     time_interval { 180 }
+    baseline_odometer { 10_000 }
+    baseline_date { Date.current }
+    active { true }
   end
 end
diff --git a/spec/models/maintenance_schedule_spec.rb b/spec/models/maintenance_schedule_spec.rb
index 5e5f882..864f3d4 100644
--- a/spec/models/maintenance_schedule_spec.rb
+++ b/spec/models/maintenance_schedule_spec.rb
@@ -6,18 +6,43 @@ RSpec.describe MaintenanceSchedule do
   end
 
   it "requires all fields" do
-    schedule = build(:maintenance_schedule, vehicle: nil, maintenance_type: nil, mileage_interval: nil, time_interval: nil)
+    schedule = build(
+      :maintenance_schedule,
+      vehicle: nil,
+      maintenance_type: nil,
+      mileage_interval: nil,
+      time_interval: nil,
+      baseline_odometer: nil,
+      baseline_date: nil,
+      active: nil
+    )
 
     expect(schedule).not_to be_valid
-    expect(schedule.errors.attribute_names).to include(:vehicle, :maintenance_type, :mileage_interval, :time_interval)
+    expect(schedule.errors.attribute_names).to include(
+      :vehicle,
+      :maintenance_type,
+      :mileage_interval,
+      :time_interval,
+      :baseline_odometer,
+      :baseline_date,
+      :active
+    )
   end
 
-  it "requires positive integer intervals" do
-    schedule = build(:maintenance_schedule, mileage_interval: 0, time_interval: 0)
+  it "requires valid numeric values" do
+    schedule = build(:maintenance_schedule, mileage_interval: 0, time_interval: 0, baseline_odometer: -1)
 
     expect(schedule).not_to be_valid
     expect(schedule.errors[:mileage_interval]).to be_present
     expect(schedule.errors[:time_interval]).to be_present
+    expect(schedule.errors[:baseline_odometer]).to be_present
+  end
+
+  it "rejects future baseline dates" do
+    schedule = build(:maintenance_schedule, baseline_date: Date.current + 1.day)
+
+    expect(schedule).not_to be_valid
+    expect(schedule.errors[:baseline_date]).to be_present
   end
 
   it "requires maintenance type to be unique per vehicle case-insensitively" do
diff --git a/spec/models/maintenance_schedule_status_spec.rb b/spec/models/maintenance_schedule_status_spec.rb
new file mode 100644
index 0000000..f7f8e70
--- /dev/null
+++ b/spec/models/maintenance_schedule_status_spec.rb
@@ -0,0 +1,58 @@
+require "rails_helper"
+
+RSpec.describe MaintenanceScheduleStatus do
+  it "marks a schedule overdue when the mileage interval is reached" do
+    schedule = build(:maintenance_schedule, mileage_interval: 5_000, baseline_odometer: 10_000, time_interval: 180)
+
+    status = described_class.new(schedule, nil, current_odometer: 15_000)
+
+    expect(status.status).to eq("overdue")
+    expect(status.reason).to include("mileage interval reached")
+  end
+
+  it "marks a schedule overdue when the time interval is reached" do
+    schedule = build(:maintenance_schedule, time_interval: 180, baseline_date: Date.current - 180.days)
+
+    status = described_class.new(schedule, nil, current_odometer: 10_000)
+
+    expect(status.status).to eq("overdue")
+    expect(status.reason).to include("time interval reached")
+  end
+
+  it "marks a schedule upcoming within five percent of the mileage interval" do
+    schedule = build(:maintenance_schedule, mileage_interval: 5_000, baseline_odometer: 10_000, baseline_date: Date.current)
+
+    status = described_class.new(schedule, nil, current_odometer: 14_750)
+
+    expect(status.status).to eq("upcoming")
+    expect(status.reason).to include("within 250 miles")
+  end
+
+  it "marks a schedule upcoming within five percent of the time interval" do
+    schedule = build(:maintenance_schedule, time_interval: 180, baseline_date: Date.current - 171.days)
+
+    status = described_class.new(schedule, nil, current_odometer: 10_000)
+
+    expect(status.status).to eq("upcoming")
+    expect(status.reason).to include("within 9 days")
+  end
+
+  it "marks a no-history schedule as no history when it is not upcoming or overdue" do
+    schedule = build(:maintenance_schedule, baseline_odometer: 10_000, mileage_interval: 5_000, baseline_date: Date.current)
+
+    status = described_class.new(schedule, nil, current_odometer: 10_100)
+
+    expect(status.status).to eq("no_history")
+  end
+
+  it "marks a schedule current when matching history exists and no interval is near" do
+    schedule = build(:maintenance_schedule, mileage_interval: 5_000, time_interval: 180)
+    entry = build(:maintenance_entry, odometer: 12_000, date: Date.current - 10.days)
+
+    status = described_class.new(schedule, entry, current_odometer: 12_500)
+
+    expect(status.status).to eq("current")
+    expect(status.due_odometer).to eq(17_000)
+    expect(status.due_date).to eq(entry.date + 180.days)
+  end
+end
diff --git a/spec/requests/vehicles_spec.rb b/spec/requests/vehicles_spec.rb
index 4fa3dc0..7947487 100644
--- a/spec/requests/vehicles_spec.rb
+++ b/spec/requests/vehicles_spec.rb
@@ -111,6 +111,7 @@ RSpec.describe "Vehicles" do
       expect(response.body).to include(vehicle.make)
       expect(response.body).to include(vehicle.model)
       expect(response.body).to include("Maintenance Schedules")
+      expect(response.body).to include("Manage maintenance schedules")
       expect(response.body).to include("Fuel History")
       expect(response.body).to include("Maintenance History")
       expect(response.body).to include(vehicle.maintenance_schedules.first.maintenance_type)
@@ -121,6 +122,141 @@ RSpec.describe "Vehicles" do
       expect(response.body.index("12,000")).to be < response.body.index("11,000")
       expect(response.body.index(newer_maintenance_entry.notes)).to be < response.body.index(older_maintenance_entry.notes)
     end
+
+    it "shows overdue maintenance alerts" do
+      vehicle = create(:vehicle, current_odometer: 15_000)
+      create(
+        :maintenance_schedule,
+        vehicle: vehicle,
+        maintenance_type: "Oil Change",
+        mileage_interval: 5_000,
+        baseline_odometer: 10_000,
+        baseline_date: Date.current
+      )
+
+      get vehicle_path(vehicle)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include("Overdue Maintenance")
+      expect(response.body).to include("Oil Change is overdue")
+    end
+
+    it "shows upcoming maintenance warnings" do
+      vehicle = create(:vehicle, current_odometer: 14_750)
+      create(
+        :maintenance_schedule,
+        vehicle: vehicle,
+        maintenance_type: "Oil Change",
+        mileage_interval: 5_000,
+        baseline_odometer: 10_000,
+        baseline_date: Date.current
+      )
+
+      get vehicle_path(vehicle)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include("Upcoming Maintenance")
+      expect(response.body).to include("Oil Change is upcoming")
+    end
+
+    it "shows no-history maintenance status without marking it overdue" do
+      vehicle = create(:vehicle, current_odometer: 10_100)
+      create(
+        :maintenance_schedule,
+        vehicle: vehicle,
+        maintenance_type: "Oil Change",
+        mileage_interval: 5_000,
+        baseline_odometer: 10_000,
+        baseline_date: Date.current
+      )
+
+      get vehicle_path(vehicle)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include("No Maintenance History")
+      expect(response.body).to include("Oil Change has no matching maintenance entry yet")
+      expect(response.body).not_to include("Oil Change is overdue")
+    end
+
+    it "logs overdue notifications only when schedule status changes" do
+      vehicle = create(:vehicle, current_odometer: 15_000)
+      schedule = create(
+        :maintenance_schedule,
+        vehicle: vehicle,
+        maintenance_type: "Oil Change",
+        mileage_interval: 5_000,
+        baseline_odometer: 10_000,
+        baseline_date: Date.current
+      )
+      allow(Rails.logger).to receive(:warn)
+
+      get vehicle_path(vehicle)
+      get vehicle_path(vehicle)
+
+      expect(schedule.reload.last_status).to eq("overdue")
+      expect(Rails.logger).to have_received(:warn).once.with(/Maintenance schedule overdue: vehicle_id=#{vehicle.id}/)
+    end
+  end
+
+  describe "maintenance schedule CRUD" do
+    before { identify_user }
+
+    it "lists maintenance schedules" do
+      vehicle = create(:vehicle)
+      create(:maintenance_schedule, vehicle: vehicle, maintenance_type: "Oil Change")
+
+      get vehicle_maintenance_schedules_path(vehicle)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include("Maintenance Schedules")
+      expect(response.body).to include("Oil Change")
+    end
+
+    it "creates a maintenance schedule" do
+      vehicle = create(:vehicle)
+
+      expect do
+        post vehicle_maintenance_schedules_path(vehicle), params: { maintenance_schedule: valid_maintenance_schedule_params }
+      end.to change(MaintenanceSchedule, :count).by(1)
+
+      expect(response).to redirect_to(vehicle_maintenance_schedules_path(vehicle))
+      expect(MaintenanceSchedule.last.baseline_odometer).to eq(10_000)
+    end
+
+    it "rejects invalid maintenance schedule params" do
+      vehicle = create(:vehicle)
+
+      expect do
+        post vehicle_maintenance_schedules_path(vehicle), params: { maintenance_schedule: valid_maintenance_schedule_params.merge(mileage_interval: 0) }
+      end.not_to change(MaintenanceSchedule, :count)
+
+      expect(response).to have_http_status(:unprocessable_content)
+      expect(response.body).to include("prevented this maintenance schedule from being saved")
+    end
+
+    it "updates a maintenance schedule" do
+      vehicle = create(:vehicle)
+      schedule = create(:maintenance_schedule, vehicle: vehicle, maintenance_type: "Oil Change")
+
+      patch vehicle_maintenance_schedule_path(vehicle, schedule), params: {
+        maintenance_schedule: valid_maintenance_schedule_params.merge(maintenance_type: "Tire Rotation")
+      }
+
+      expect(response).to redirect_to(vehicle_maintenance_schedules_path(vehicle))
+      expect(schedule.reload.maintenance_type).to eq("Tire Rotation")
+    end
+
+    it "soft deactivates a maintenance schedule" do
+      vehicle = create(:vehicle)
+      schedule = create(:maintenance_schedule, vehicle: vehicle, active: true)
+
+      expect do
+        patch deactivate_vehicle_maintenance_schedule_path(vehicle, schedule)
+      end.not_to change(MaintenanceSchedule, :count)
+
+      expect(response).to redirect_to(vehicle_maintenance_schedules_path(vehicle))
+      expect(schedule.reload).not_to be_active
+    end
   end
 
   describe "POST /vehicles/:vehicle_id/fuel_entries" do
@@ -368,6 +504,17 @@ RSpec.describe "Vehicles" do
     }
   end
 
+  def valid_maintenance_schedule_params
+    {
+      maintenance_type: "Oil Change",
+      mileage_interval: 5_000,
+      time_interval: 180,
+      baseline_odometer: 10_000,
+      baseline_date: Date.current,
+      active: "1"
+    }
+  end
+
   def identify_user(user = create(:user))
     @identified_user = user
     access_key = AccessKey.current