Built-in batteries mean a built-in expiry date for gadgets: lithium-ion batteries slowly lose their ability to hold charge over time, eventually dying an ignominious death, and rendering your expensive gizmo useless — unless, that is, you've got AppleCare.
In a small change to the policy for AppleCare for Mac spotted by MacRumors, Apple will now cover batteries that hold less than 80 per cent charge. Previously, only 'defective' batteries were covered — meaning you could probably talk your way into a free replacement with a kind employee, but you're basically now guaranteed a fix.
If you don't have AppleCare, a replacement will cost you somewhere between $US130 and $US200, depending on your laptop model. Given that AppleCare itself runs between $US250 and $US350 for three years ($279 and $389 in Australia), and your battery is virtually guaranteed to wear out in that time, it's looking like a better and better deal.