Interesting. I enabled iTunes Remote on the Apple Watch. Listened to iTunes Radio and several playlist for a good 6 hours or more. Apple Watch is connected to control iTunes Remotely. When I finally turned off iTunes on the iMac, I received a Low Battery Warning several minutes later. It quickly dropped to 10% then 9 then 8... I don't think I will use the Apple Watch as a remote iTunes control on the iMac (late 2013). It's a massive battery drain for a feature.