Move down to only 1 abstract data type with a nully Frequency. Should aid in making the Expense page usable for all 3 data type.

lib/models/tracked_item.dart

@@ -0,0 +1,49 @@
+// Local
+import '/models/frequency.dart';
+
+abstract class TrackedItem {
+  int? id;
+  String name;
+  double amount;
+  Frequency? frequency;
+  String description;
+
+  TrackedItem({
+    this.id,
+    required this.name,
+    required this.amount,
+    this.frequency,
+    required this.description,
+  });
+
+  static String amountText = "Amount";
+  String getAmountText() => amountText;
+
+  @override
+  String toString() {
+    return toMap().toString();
+  }
+
+  double calcComparableAmountYearly() {
+    return frequency == null ? 0 : amount * frequency!.timesPerYear;
+  }
+
+  double calcComparableAmountDaily() {
+    return frequency == null ? 0 : amount / frequency!.numDays;
+  }
+
+  Map<String, dynamic> toMap() {
+    return frequency == null ? {
+      'id': id,
+      'name': name,
+      'amount': amount,
+      'description': description,
+    } : {
+      'id': id,
+      'name': name,
+      'amount': amount,
+      'frequency': frequency!.title,
+      'description': description,
+    };
+  }
+}