i am pretty paranoid about battery life in all my fancy electronics. with many devices you must wait until the charge is relativly empty until you can recharge it. first is this the case with the 3g or can i charge it any time without worrying that it's depleting battery life. i want to get one of those bose sound systems for my iphone or something that resembles it. whenever you plug your iphone in though it charges if the iphone should only be charged once the battery is dead how do i use the sound system without killing the batter life.