I have been using the lite version of Due Today (1.4.6) to remind me to check email accounts on a recurring basis. Some require that you log in at least once every 30-60 days, so I set it up in Due Today to repeat when completed. However I noticed that if I mistakenly tap twice to complete it, the due date is incremented again. The first time it gets incremented 30 days (if that is the Repeat value), but the next time you tap it, the due date gets set 60 days in the future.
Perhaps you could add a warning, setting or some validation to prevent adding too many days to the next due date? If you tap the checkbox to complete it today, the repeat date resets the due date. If you tap again, it should still set the next due date to be x days/weeks from today, not x days from the next due date which may already be at least x days in the future.
