The writer’s iPhone 15 Pro Max has reached 1,000 charge cycles after nearly three years and reports 81 per cent battery health. Its battery life has fallen from more than 12 hours of screen-on use when new to often needing a charge before the day ends, illustrating how battery wear affects everyday use even before iOS issues are considered.

Apple designed iPhone 15 models and newer to retain 80 per cent of their original battery capacity through 1,000 cycles; iPhone 14 models and older were rated for 500 cycles. The writer says software updates also affected their experience: iOS 18 and 26 brought performance and battery-life frustrations, while the early iOS 27 beta felt smoother. The phone still needs charging at least twice daily, but its battery health has not yet triggered a service warning.