I don’t use it a lot and I keep it plugged in some majority of the time. It only charges to 80%. I also occasionally, probably every month, drain the battery to zero.
Also, the majority of time it’s been in my van, which is pretty chilly most of the time.
From my understanding, battery health is based on use and environment.
I have been monitoring temperatures closely with mac-stats https://mac-stats.com/ over the last few months.
It typically runs around 110-130 for CPU and the battery is 85-90 on light usage like say browser or slack.
However if i run a full compile of the repo or just about anything a bit compute intensive CPU jumps easily to 170-200 range regularly and battery to 120.
I am now frequently running the fans higher manually to cool it down[1]
I think Apple is optimizing for being quiet over battery and laptop life and have kept the fans low speed even if it would benefit the hardware to speed them up earlier under load.
[1] This is not because I can the temps all the time in the top bar. The palm rests do become noticeably hotter and bit uncomfortable than the noise would be.
Also, the majority of time it’s been in my van, which is pretty chilly most of the time.
From my understanding, battery health is based on use and environment.