Here is our current retention plan
It seems we are removing everything we can. But if we go back to instances completed years ago you can still find all the submission data, and action history.
When we open a task from an old process we get the notification here:
But I can still see an image of the form with all the data and all the action pane history.
Holding all this data forever is causing an unhealthy amount of storage needs
Update: It seems that even with all the boxes checked Forms keeps almost all the data in history anyways. We opened a case, 24508, in January and it is now April with no resolution. This means Forms databases will grow infinitely.