When I used to get Apple Care, the fine print said that if the battery capacity fell to 50% or below, within the warranty period (2 yrs) they will replace the b

When I used to get Apple Care, the fine print said that if the battery capacity fell to 50% or below, within the warranty period (2 yrs) they will replace the battery (swap phones). This worked for me twice. Ironically, I stopped getting it because the batteries seemed to get better and better every year.