After talking to a few members about sleep tracking apps, settings, and battery life, I decided to pay attention to my settings and battery life and keep track of it last night when sleep tracking. Usually I charge my watch in the morning after sleep tracking, but last night I charged it before bed so it would be at 100% Monday Night I took the Watch off the charger at 10:15 pm and had 92% battery remaining after 8 hours. Series 4 Watch 44mm running WatchOS 5.0.1 iPhone X running iOS 12.0.1 Settings: I was running AutoSleep, but I force quit any other app that was running in the background. Inforgraph Digital watch face Turned on Do Not Disturb, Theater Mode, and Mute. (Airplane Mode was not enabled). I recently turned off "auto detect gym equipment," as I don't use this feature. Raise to speak - Off Brightness - Max [Update] Tuesday Night Same settings as above, but with Airplane Mode enabled 93% battery remaining after 8 hours, so 7% usage. Obviously, the minor decrease in battery usage might not be due to Airplane Mode but possibly to me tossing and turning less. It's a small difference, but I'll keep an eye on it. [Update] Wednesday Night Last night I changed things around and didn't charge my watch before bed, so it was off the charger being worn since Tuesday night. Went to bid with 63%, and got out of bed 7 hours later with 54%, so 9% usage after 7 hours. [Update] Thursday Night I haven't charged my watch since Tuesday night, so it was at 25% when I went to bed last night. After 7 hours it's at 13%, so 12% usage after 7 hours. So the last time my watch was on the charger was Tuesday night, and I've worn it for 3 nights in a row without charging. Tuesday night, when I started with 100% battery, I used 7% after 8 hours. Wednesday night I started with 63% battery and used 9% after 7 hours. Thursday night I started with 25% and used 12% after 7 hours. It seems like my usage increased a little bit each night the further away I am from a full charge (at least for these past 3 nights). I'm not sure if my battery usages is actually increasing, or if it's just how the Apple Watch battery meter works. I notice when it's at 100%, it likes to stay there for quite some time before it starts dropping. I'm going to see how long my watch lasts until it runs out of juice today, and see if that affects my calibration of the battery meter. [Update] Friday Afternoon Battery finally died. The last time I checked my usage was 2 days, 15 hours of standby, with 5 hours, 5 minutes of usage. Decreasing my brightness from max would probably stretch this out a little. It was charged to 100% in a little under 2 hours. [Update] Friday Night I had an interesting development last night. I had 95% battery remaining after 7 hours and 15 minutes, for 5% battery usage. After letting my battery run down all the way yesterday, I left it on the charger and put it on before bed. I force quit all the apps, but I forgot to launch AutoSleep and hit lights out. This was the least amount of battery I've used over a 7-8 hour period, so I'm wondering if it was from calibrating my battery, or from just having no apps open (not even the sleep tracking app). An interesting side note is that the sleep tracking seems more accurate without hitting "light out" in AutoSleep. AT least for me, it's been counting me as asleep when I'm lying in bed motionless in the morning, but today it should I was awake for about 20 minutes that it normally would have counted as asleep. [Update] Saturday Night I wore the watch all day and went to bed with 62% and got up with 55% after 8 hours, for 7% battery usage over 8 hours. I did force quit all apps, set theater mode, mute and do not disturb as usual I didn't launch AutoSleep, and it seems to consume a little less battery while being at least as accurate if not more. I'm not going to charge the watch today so I can compare the 3 nights in a row from before I calibrated the battery meter to after. [Update] Sunday Night Haven't charged the watch since Friday. Went to bed with 26% and after 7 hours had 16% for 10% usage over 7 hours. After last night, I've come to the conclusion that the battery meter will drop more quickly the further away it is from 100% In other words, 100%-95% is the same amount of battery consumption as 25%-15%. This past week, two times there were 3 consecutive nights where I did not charge the battery. Each night I used progressively more battery. Full charge Tuesday 7% Wednesday 9% Thursday 12% Full charge Friday 5% Saturday 7% Sunday 10% It's not a completely scientific conclusion, the battery meter dropping more quickly the further it is from 100%, but all conditions and settings were the same for all 6 nights.