TimeAcappella lets you know when it's time, then more often as the date gets closer. Once the date has passed, it carries on, less and less often: it doesn't forget, but it doesn't nag. Tapping “Done”, or noting an appointment, stops the reminders.
What time they arrive
Reminders arrive at the time you choose in Settings, Reminders, “Reminder time”, never between 9 pm and 8 am. If there are several on the same day, they arrive together.
Summary
Every week or every month, on the day you choose, a reminder tells you how many things there will be to plan. “Never” turns it off.
Before an appointment
“The day before” reminds you of an appointment you've booked, at the time you chose; “A week before” adds a reminder eight days earlier. The day after the appointment, the app tells you it has been counted as done.
For a loved one
On a contact's card, use “Their reminders” to choose how their reminders come: “One by one”, only “In the summary”, or “None”. See Plan for a loved one.
Which device
Only one of your devices sends the reminders, otherwise they would arrive twice. By default, it's your phone, the one you always have with you. If you have several devices on your account, choose which one in “Reminders arrive on”.