For reference sake, I have a 42mm SS Apple Watch and an iPhone 6Plus 64gig AT&T I have read a lot of posts about poor battery life and how much the iPhone is drained by the watch so I wanted to post my results as a comparison. I have now tested this for over a month. I charge my watch every night at 9pm and by 10pm (easily) it is fully charged (usually around 50% starting point). I wear my watch to bed as my silent alarm and I disable wrist raise and do not disturb is active. I normally sleep 7 hours and the silent alarm wakes me and the battery life 94% +/- 1%. Tuesdays are my most active days and here is the breakdown. 5:30am and battery is at 93% - 1 hour 20 minute workout using the Workout app set to Other. 900 calories with a workout that was lifting weights, walking on the treadmill for warmup and all rest periods and then HIIT for 20 minutes and cool down. Battery is now at 79% Go about my work day with numerous notifications, replying to text messages and using siri - plus using Fantasical 2 (great app) and 2Do (great app) for appts and reminders. at 4pm, my watch is at 65% Golfed 9 holes - walking and carried my clubs in 85 deg temp. Used the Workout App set to Other. The iPhone 6plus was in my bag fully charged to 100% and connected to my watch on my arm the entire time. Numerous notifications and even replied using canned responses and siri - most I ignored. I did not use a golf app. 2hours and 5 minutes later, and 1050 calories, the watch read 44% and the iPhone 6 plus was at 99%. at 9pm, the Watch is at 30-35% and this is my most active day. Without golf, my Watch is usually at 50-55% These numbers have always been close to the same with the iPhone usually at 100% after 2 hours. I don't understand how others are saying the iPhone is draining even when not in use and connected to the Watch because mine is not moving much at all - even with the blue-tooth connection. Though, I was not using any apps except a few replies using siri or canned responses. The Workout app didn't drain it ever. Finished the day registering 2003 calories, 205 minutes working out and standing for 14 hours. After reading so many posts about poor battery life and iPhone draining, I must not be using enough apps that drain the Watch and Phone. Best Apps are Fantastical 2 and 2Do (got during free week) - I use these all the time with zero delay and has all my calendars and todo's and the calendar is on my Watch home screen using Modular. I think the battery is fantastic but when I see any sign of a quicker battery drain (once every few weeks) I shutoff the Watch and back on and may just do this each night right before charging. Hope this helps.