My 2010 MacBook Air, which is 20 months old according to coconutBattery, still holds a four hour charge. This machine was fine for the final two years of my degree. Hell it can even play Diablo 3 pretty well.

I would expect to make a return on my investment when I sell it later this year. No other manufacturer can claim results like this.

A MacBook Pro will have an even longer life, this is just a 1.4GHz processor.