Series 8
with absolutely everyone turned fully on (no attempt to power save anything).
with approximate 70 - 90 minute workout (running, daily).
with using it to track sleep at night.
with 2 or 3 purchases daily with apple Wallet cards.
i get > 15 hours.
usually my iPhone is in my pocket so its usually close to the Watch.
with WatchOS 10 i get between 15% and 25% battery charge remaining when i start to charge it for about 1 hour just before i go to bed.
with WatchOS 9 i got between 20% and 30% battery left before i charge it.
the Workout with all fitness measurements fully working is definitely the heaviest drain on the daily battery life.
also: i have noticed when i use the Watch to make 2 or 3 calls (its a cellular model) of maybe 5 or 6 minutes each, the battery will drop to around 5% - 10% remaining when i begin to charge it at night.
i do have express transit turned on, so theoretically that should be giving a percentage showing less than it actually has.
very satisfied.