My girlfriend's Macbook Pro starting giving her an error about her battery not properly charging. Seeing as how I had the same model and I was getting a new one, I decided to give her my laptop's battery instead of forking out the cash to have the Apple Store fix it.
The repair went extremely smooth thanks to the instructional video and the tools that iFixit sent to me.
I would recommend anyone with half a functional brain and at least one working appendage to research electronics repairs online prior to paying someone hundreds of dollars to fix a relatively easy problem that is said to be, "only handled by the professionals." You'd be surprised how simple some of these issues are to tackle on your own! :D