This probably should not have come as a surprise but we did notice something yesterday as my Wife and I both set up 2nd watches (Yes, it's basically a fashion accessory so we wanted more variety). The new watch can be set up by restoring it from the most recent back-up of your existing watch of course. But until you put the new Watch on your wrist the Apps don't install on it. So after you first put it on you may notice the battery going down quickly. I suspect the same would be true if you have any playlists synced to your Watch too. It's been mentioned on here a few times that when you have multiple watches paired to a phone all your move data does sync back and forth as you change from one to the other. Anyway it's not a big thing but thought I would mention it. There must be others out here who have 2 or more Watches now and maybe you too have discovered something that might help others too. Please feel free to add your own discoveries, tips and tricks to the thread.