Many apps help you remember things, but very, very few allow you to have repeating reminders that you can choose to repeat from when you've completed it rather than a fixed schedule or when the reminder was due.
Remember is designed to specifically address this deficit.
I wear contact lenses, and am too scatter-brained to remember exactly what day last month I last changed them and occasionally I manage to drop one or I was out of lenses and the shops were closed so I have to wear the old ones more day.
Remember solves this by letting you complete reminders before the due date or after, while still advancing the time until the next reminder by the set amount of time.
As a bonus, it can also use the due date as a base for when to advance reminders.