If you are creating a project and would like all associated tasks in that project to be removed from your users' task list after the due date/time, simply leave the checkbox beside Auto Archive on the projects page checked.
Selecting the box will automatically move the project to your archive folder once the due date has passed.
You will still be able to see the project and all of its related data in the archive section of your projects folder.
Unselecting the box will allow for the tasks to remain open even after the due date has passed and will add up if a lot of tasks are not completed.
Please feel free to reach out to firstname.lastname@example.org if you have any questions or concerns.