Battery life for my 09HR is pretty good. A pair of Duracell Ultras last thru a 4 hour show and still have more than a half a life left. And that is with another deck or headphones patched into it. When you turn down the display and kill the red blinking record light, it does save a lot of energy. I also used regular Duracells at a 4 hour show recently, patched in another deck and came home with a 1/3 life left. In general, I don't see any need to go more than 5 hours of taping for any show I see. Of course I don't use re-chargeables. Can't trust them...