The day I was flying, I put the phone in Airplane mode and listened to audible books with my noise canceling headphones plugged in, Ran audible app for 5 hours straight and used 15% of the battery. I don't like to baby the battery life either, I just like having a spare to swap when I need to. My old win Mobile PDA, I used to have three batteries, two thin ones and one double size which is probably what I'll end up with on this Thunderbolt. My wife's LG env3 can go for a week on a charge but then that phone can't do sh!t. What it can do is rather 1990's. Give me the power in the device and I'll find a way to keep it powered.