So I have a late 2008 model uMBP that I bought refurb from the Apple Store in July. (Great deal) Anyway, I am only getting 2:10 hours of battery life, on average, when it isint plugged in. And that is with the wifi off, bluetooth off, no applications except for microsoft word, (taking notes in class) Is this normal? I thought the 2008 models are getting 5.5 hours with "wireless productivty" too! Should I get a new battery?