I have found if you turn off the widgets running in the background, wifi off, and 3g off with moderate use you can get almost 2 days. with heavy use, I would say maybe a day. I just turn off my phone at night, and turn it on in the morning, that way i can charge it every other day. On a side not I have no data plan and can access Wiifi to pull emails and dload market apps. The reason I have no data plan is because I got the phone on ebay, that's the trick if you have a wifi connection, it works. In my humble opinion this is the best android device for t-mobile. I had the G1, MT3g, and tried the Behold 2, i really hope they update to 2.0 soon, or at least 1.6, maybe before Xmas