Since 2023, Apple's newer iPhones have had an 80 percent charge limit for those who want to extend battery lifespan. Charging to 80 percent instead of 100 percent is supposed to put less stress on the battery, improving longevity. For the last three years, I've used that setting on my iPhone. I started with the iPhone 15 Pro Max , then did the iPhone 16 Pro Max , and most recently, the iPhone 17 Pro Max. After 12 months at an 80 percent maximum charge, my iPhone 17 Pro Max is at 97 percent maximum capacity with a cycle count of 277. Last year, my iPhone 16 Pro Max was at 94 percent capacity after 12 months, and in 2024, my iPhone 15 Pro Max was also at 94 percent capacity. During the year I tested the ‌iPhone 16‌ Pro Max, I tried not to let the battery dip below 20 percent. This year, I did the same thing, but I also tried to do more charging over USB-C than Qi2 or MagSafe . I'm not sure if that helped, but 97 percent capacity is the best result I've had yet with the charge limit turned on. I don't know how my battery result compares to others, but if you've kept yours at 100 percent, you can compare your capacity to mine to see if there's any real difference. Apple transitioned to aluminum and added vapor chamber cooling with the ‌iPhone 17‌ Pro Max, and I did think my iPhone spent less time uncomfortably warm than the ‌iPhone 16‌ Pro Max.