I picked up a Milwaukee 18v Fuel 1/2" impact (model 2763-20) today, and it came with one 5.0ah battery. I know this is a difficult question to answer, but how much life do you typically get out of one battery (on an impact)? Reason I ask, I am trying to decide if its worth adding a second battery....my Matco 3/8" impact only came with 1x battery, and it hasn't been an issue. Of course, I've yet to run it really hard, and have a feeling I may get a little more use out of the Milwaukee.