My 11 PM from launch day had gone from 100% to 85% in 11 months, then apple released that calibration fix towards the end of first year, it climbed up to 87%, then went down to 84% by end of year 2, then 82% by end of year 3. It was my daily driver, I used it heavily for work, many charging it twice in a day. But I never had any battery issues so to speak.

I sold it when I bought my 14 PM at launch.