My 13" MacBook Pro is now over 3 years old. The battery has been dying slowly from day one. I mean, that's what batteries do anyway, right? Mine seems to have picked up a bit of a death wish though as it's been dying faster and faster. For a while now the battery status indicator has been displaying the ominous "Service Battery". It was time for a transplant.
After a short search iFixit turned out to be the #1, most reliable and trustworthy source of a replacement battery so without further ado I ordered one. Now, I live waaaay across the world in New Zealand yet ordering from iFixit couldn't be easier. The battery arrived promptly and the whole repair cost me a lot less than if I had my MacBook serviced by the local rip-off merchants.
Ergo — one happy customer!
10 screws, 2 screws, pull, push, 2 screws, 10 screws... it really was THAT easy.
If you need a replacement battery and your MacBook is out of warranty, just replace it yourself. It's really easy and safe.