MemoTank is a worldwide provider of sending email reminders + push notification.
It allows you to set an "alarm" which will fire when you need it (possibly in a few years from now).
In order to use this service, all you have to do is set the date and the time and provide your email address.
You can also provide a description that will arrive together with the memo at the scheduled time.
The "memo to email" service is totally free and unsubscription is possible anytime.
With Family Sharing set up, up to six family members can use this app.