I've got a Series 10. I've got "always on display" turned off because I do not find it useful. I've got optimized charging set to try to limit it to charging to 80%.

I generally put it on the charger every evening around 7 pm or so when I sit on the couch to do the NYT crossword and Sudoku (which come out at 7 pm in my time zone) and watch some TV or read for a while.

It then goes back on my wrist but in theater mode and with notifications silenced until morning.

It generally uses maybe 5-10% while I sleep. In the morning I turn theater mode off and un-silence notifications, and then use it to track 30-35 minutes of exercise.

It is typically still above 30% when it is time to do the next crossword.