It's a small battery, so it doesn't take long to charge. I usually charge mine in the evening while my wife and I are just hanging out.
I go to the gym at 430am, then workout, when I get home I throw it on the charger while I get kids up and get ready for work etc. This charges to 100 percent then repeat the process the following day or following night while getting ready for bed. Works great once you have a system down
I put mine (42mm Space Grey) on at 7am in the morning, and wear it until I get home at 6pm, whereby I then put it on my nightstand where I have the charger. I then go to bed at around 11pm - I guess I could then put it on to track my sleep, and then throw it back on the charger again at 6:45am when I wake up, whilst I wash and stuff, and then put it back on again at 7am, ready for the rest of the day?
What kind of straps do you guys wear for sleep tracking then? I currently wear a Belkin black leather band, which is nice and comfortable during the day, however, wouldn't have thought this would feel nice during the night?! Perhaps a sport band (but that then would mean, switching out the bands every night and every morning - a chore!!) ?
..and do the various sleep tracking apps (I don't think the watch natively tracks sleep does it?) write to the Health App?