DueDay
Remember when you last did it, and when it's due again.
DueDay is a small, free iPhone app for the things you do every few weeks, months or years: a car service, the dentist, an air filter, a passport renewal. Add an item, tap Mark Done when you do it, and DueDay shows when it's due next. Days To Go counts down to the dates that matter.
Everything stays on your iPhone. No account, no ads, no tracking.