Nuzzlewuzzles you

Why use apple care when it’s a warranty issue

Yes 20% degradation within a year is of course a warranty issue

It’s not only a bit of a cash grab; it’s very wasteful and harmful to the environment.

For reference I replaced my daily 8+’s battery 3 years ago and I’m at 76% with no degradation in performance (aside from the “new OS, who dis?” features designed for the newest hardware). Lithium batteries aren’t an annual replacement item and we shouldn’t test them like that

Either you have some very odd charging habits your you have a faulty battery. 15+% within one year is well outside of an acceptable degradation of product life

When Apple recommends a new battery and when performance decreases due to battery% aren’t the same at all. I’ve had devices in the 60%s before it started to impact performance.

80% is a bit early to be replacing the battery unless it’s faulty, iPhones won’t even pull performance at that battery health. This battery is probably a lot lower than that to be triggering the performance management settings