Like a lot of people, I've been having very poor battery life. Perhaps 2 hrs usage + 10 hours standby. The Usage monitor (under Settings) has never activated despite the battery supposedly having a full charge (i.e. when the battery icon in the upper right corner changes from the lightening rod to the plug). Previously I had tried: (1) draining the battery completely and then doing a full charge; and (2) reinstalling the software. Neither made a difference. I took mine to the Genius Bar today and guy in front of me was having the same problem. The tech replaced both of our phones, no questions asked. He switched out my sim card and I walked away with new 8 gig. I need to sync with iTunes to unlock, but don't need to reactivate. Bottom line, I think some phones just have bad batteries.