How long can I pay for Apple Care

You have 2 options when you buy the phone. You can either buy AppleCare for 2 years, or you can pay monthly for as long as you want. Additionally, when your 2-year AppleCare plan runs out, you have 30 days to switch to a monthly plan.

For more information, take a look at this link:

Buy an AppleCare plan - Apple Support

As long as Apple offers a monthly plan, you can pay for it. But we do not know how long that will be.