Hello guys:
I have written down on google sheet all battery cycles (charge and use) since I bought my watch in April 2021
My best record was 8 days, the worse 2 days 4hours .
I leaved notes specifying what setting I had in each round.
Things that consume lots of energy (battery) SpO2 (pulse oximeter) , GPS, Messages updates.
I don't check messages on my watch so that's always off. I prefer to read on my phone.
Depending on how you use your watch and for what purpose, you can change the settings to maximise battery life.
https://docs.google.com/spreadsheets/d/1wKjYnWZLgx5Hu9PvJ907QWrVZM4SGvIrnb2wnuvEpkA/edit?usp=sharing
Hopefully this can help you knowing what's better for you and what to expect from your watch.
cheers