Im getting about 5.5 hours when I am 3g with my 3gs. This is pretty good, a bit more then my old 3g and what apple estimated with the defaults. However, I have GPS is off, Brightness is 25% without auto-brightness, Turned off fetch new data and push, and Turn off ask to join wifi. This pretty much what I hoped for but when I turn off 3g with the same settings I still only get 5.5 hours of usage on wifi. I don't understand, my old 3g last a lot longer on battery when I was on wifi and apple says it should last 9 HOURS. I tried this several times and even restored before the last time I tried. How long are your phones lasting?