diff --git a/packages/flutter_availability/lib/src/service/availability_service.dart b/packages/flutter_availability/lib/src/service/availability_service.dart
index b995fe4..4ae9ef1 100644
--- a/packages/flutter_availability/lib/src/service/availability_service.dart
+++ b/packages/flutter_availability/lib/src/service/availability_service.dart
@@ -44,7 +44,7 @@ class AvailabilityService {
       userId: userId,
     );
 
-    await dataInterface.createAvailabilitiesForUser(
+    await dataInterface.setAvailabilitiesForUser(
       userId: userId,
       availability: updatedAvailability,
       start: range.start,
diff --git a/packages/flutter_availability/lib/src/service/local_data_interface.dart b/packages/flutter_availability/lib/src/service/local_data_interface.dart
index a1eb5c6..79480d0 100644
--- a/packages/flutter_availability/lib/src/service/local_data_interface.dart
+++ b/packages/flutter_availability/lib/src/service/local_data_interface.dart
@@ -47,7 +47,7 @@ class LocalAvailabilityDataInterface implements AvailabilityDataInterface {
   }
 
   @override
-  Future<void> createAvailabilitiesForUser({
+  Future<void> setAvailabilitiesForUser({
     required String userId,
     required AvailabilityModel availability,
     required DateTime start,
diff --git a/packages/flutter_availability_data_interface/lib/src/data_interface.dart b/packages/flutter_availability_data_interface/lib/src/data_interface.dart
index 7434dc0..0ae9c1c 100644
--- a/packages/flutter_availability_data_interface/lib/src/data_interface.dart
+++ b/packages/flutter_availability_data_interface/lib/src/data_interface.dart
@@ -37,14 +37,17 @@ abstract interface class AvailabilityDataInterface {
   /// Updates the availability for the given [userId] and [availabilityId].
   ///
   /// This will not work if no [availabilityId] for [userId] exists.
-  Future<AvailabilityModel> updateAvailabilityForUser(
+  Future<void> updateAvailabilityForUser(
     String userId,
     String availabilityId,
     AvailabilityModel updatedModel,
   );
 
-  /// Creates a new persistant representation of an availability model.
-  Future<void> createAvailabilitiesForUser({
+  /// Creates / Updates availabilities for each day in range [start] ... [end].
+  ///
+  /// [end] is an inclusive date. [start] and [end] are processed ignoring any
+  /// non-date related information.
+  Future<void> setAvailabilitiesForUser({
     required String userId,
     required AvailabilityModel availability,
     required DateTime start,
@@ -74,20 +77,20 @@ abstract interface class AvailabilityDataInterface {
   /// Updates the availability for the given [userId] and [templateId].
   ///
   /// This will not work if no [templateId] for [userId] exists.
-  Future<AvailabilityTemplateModel> updateTemplateForUser(
+  Future<void> updateTemplateForUser(
     String userId,
     String templateId,
     AvailabilityTemplateModel updatedModel,
   );
 
   /// Creates a new persistant representation of an availability template model.
-  Future<AvailabilityTemplateModel> createTemplateForUser(
+  Future<void> createTemplateForUser(
     String userId,
     AvailabilityTemplateModel template,
   );
 
   /// Applies a given [template] for a [userId] and creates new availabilities.
-  Future<List<AvailabilityModel>> applyTemplateForUser(
+  Future<void> applyTemplateForUser(
     String userId,
     AvailabilityTemplateModel template,
     DateTime start,