* Subscriptions are for one year at a time, and have transparently indicated pricing. No "$2.71 per day, charged annually", no hidden tips, taxes or convenience fees.
* If you don't use the app for a few months, they auto-extend your subscription by an extra month as a courtesy.
* When your annual subscription is about to expire, they send a reminder a few weeks and another a few days before the expiration. If you don't renew, you get a final "Sorry to see you go, here's how to reactivate for $annual_price, if you don't renew we'll delete your stored data in a few months" email.
This is how subscriptions should work. They send an appropriate amount of notification at a good schedule to make sure you don't accidentally forget to renew, and don't pester you to death if you don't.