I just found out that you can quit apps on the ipod touch by holding the home key for about five seconds, instead of just pressing it once to go to the home screen. This may seem like a silly question, but is it better for battery life to close apps when you're done with them or just leave them running in the background? If it takes up a lot of processor power to start up an app that isn't running, like when the ipod touch boots up, then quitting apps might actually use up more battery. On the other hand, having apps stay open might use up more cpu cycles, which would also cause the battery to drain. Is it better to quit apps or leave them open?