I need to do repeating tasks that are not precise, but are periodic intervals - weekly, every 3 mos etc - based on the date I completed the task. Not a set date.

Example: I need to do something once every 3 mos. (change AC filter). So, if I do the task before or after or on the repeat date - once I check off as done, 3 mos adds to that done date.

Monthly dog meds - no precise date needed. Just a reminder set and once I give them meds/complete - a month/4 weeks etc is automatically added from that completed date.