What is the last point to replace the battery capacity

It is a good idea to replace the battery when the Battery Health drops to 80%.

I changed the battery to 82% because it started to get very hot when I used it. There were times when that message with "the phone is too hot" appeared and I said it was time to change it.

if your phone is operating in normal settings and you don't feel like you're having problems with it, it's not worth changing the battery