It depends on the plan you choose.
- "Lifetime" plan — a single payment, after which you can use the Premium Service forever. No monthly or yearly charges
- "Monthly" and "Annual" plans — renew automatically every month or every year. You can cancel at any time from Google Play
With any plan, as long as you use the same Google Account, you can keep using the Premium Service without paying again when you switch phones or buy a new tablet.
Once you have paid for the Lifetime plan, you can continue enjoying the app indefinitely, so the longer you use it, the better the value. We hope you'll consider it.