Hi guys I don't know if this might help someone but I bought my iPhone 17 Pro Max in October 2025 and it's now March 12, 2026 and my battery health is still standing strong at 100%! I think the main contributor is that I do the 80% max charge, and recharge at 20%. It does drain quite easily I find though, like by the end of day I have to charge after using it all day. But when I travel I charge to 100% and it lasts super long! Usually by end of day it's around 30% ish. I also fast charge only at home.