The current behavior in Alma is that any calendar entries have an effective date and a valid until date, that is automatically 3 years beyond the date the event was last edited.

The effective date does not in my mind serve any purpose and creates puzzling and frustrating situations for fulfillment services staff if the current date approaches any of these valid until dates, because patron loans will start being shortened, seemingly for no reason.

For exceptions, date ranges are called explicitly. For standard hours there either should be no valid until date, or this should be specified explictly, to match the behavior of exceptions. If no date is given then the hours in that entry should persist indefinitely