(I posted this also under Samsung Focus, but I've no idea whether the problem is specific to the phone or is a Windows Phone issue) On some days, my SamsungFocus will finish the day with a healthy charge left, and others it will run out after 6 - 8 hours or so. Note that this is often while merely sitting in my pocket with next to no usage. I think I've checked the usual suspects: No background tasks Bluetooth is off Location is off Battery saver "on when battery is low" Screen timeout - 3 minutes I keep Wifi on because I'm more often using that than cellular, and a few times I've forgotten to switch to WiFi, incurring data charges. Typically, I plug in the charger at bedtime. Then I read RSS feeds for a while. Leave it charging overnight. About 1 day in 4 or 5, it will run out of juice in that 6 - 8 hours even if I haven't used the phone at all. No pattern that I can discern. We did try a new battery -- no help. Thoughts/suggestions? Thanks.