I was thinking of doing that, S3 for sleeping/rough stuff, S8 SS for non-rugged daily use. Then I got the Ultra and with the extra battery I just use it all the time, swapping bands. (Ti link for work and “formal”, Alpine for casual, stretchy loop for sleep)
Extremely happy with the Ultra for this use case.
It charges so ridiculously fast compared to my previous S3. Right now it’s 7am, I have 49% remaining. My watch was last charged to 93% Sunday night at 10pm. If I work out today I’ll charge during my shower after, otherwise I’ll do a quick charge at night before sleeping, it’ll probably take 30 minutes while I’m getting ready for bed and stuff.