Begin making the Expense page more arbitrary for future re-use by creating superclasses which will fit all 3 object use cases.

lib/models/expense.dart

@@ -1,51 +1,24 @@
+import '/models/recurring_tracked_type.dart';
 import '/models/frequency.dart';
 
-class Expense {
-  final int? id;
-  final String name;
-  final double cost;
-  final Frequency frequency;
-  final String description;
+class Expense extends RecurringTrackedType {
+  static String amountText = "Cost";
 
-  const Expense({
-    this.id,
-    required this.name,
-    required this.cost,
-    required this.frequency,
-    required this.description,
+  Expense({
+    super.id,
+    required super.name,
+    required super.amount,
+    required super.frequency,
+    required super.description,
   });
 
-  @override
-  String toString() {
-    //return "$name, $cost, ${frequency.title}, $description";
-    return toMap().toString();
-  }
-
-  double calcComparableCost() {
-    return cost * frequency.timesPerYear;
-  }
-
-  double calcComparableCostDaily() {
-    return cost / frequency.numDays;
-  }
-
   factory Expense.fromMap(Map<String, dynamic> json) => Expense(
         id: json['id'],
         name: json['name'],
-        cost: json['cost'],
+        amount: json['cost'],
         frequency: Frequency.values
-            .where((expense) => expense.title == json['frequency'])
+            .where((freq) => freq.title == json['frequency'])
             .first,
         description: json['description'],
       );
-
-  Map<String, dynamic> toMap() {
-    return {
-      'id': id,
-      'name': name,
-      'cost': cost,
-      'frequency': frequency.title,
-      'description': description,
-    };
-  }
 }