I run it continuously through the full lifting routine. I normally end my workouts with some cardio (Elliptical, bike, treadmill, rower) for those, I’ll switch workouts to the explicit exercise.
I will pause for a bathroom break or extended conversation though.
I had to return my three year old S6 (loaner for a heart research study) and replaced it with an SE gen2. It’s perfect for me, I’m glad I didn’t pay twice as much for an S9 or even more for the ultra.
Mine wouldn’t update from the cloud until I upgraded it to the latest version and I always charge it while installing an upgrade. It was a long upgrade and was at 100% when finally complete.
Normally, I charge it after I wake up while having coffee, and I take it off while showering to keep it away from soap residue.
As far as salt water affecting it, just rinse under tap water when you get out. I’d be more worried that it would fall off.
I also rinse it after a shower because of soap residue.
I had an S6 for 3 years, and recently upgraded to an SE2. I’m happy, I don’t miss anything and couldn’t justify the difference in cost to get an S9.