Third Battery for my '07 Macbook. The older ones got swollen, no free replacement. The 1st battery was messing up my trackpad and was swollen; the 2nd battery still holds a very good charge but it was swollen and making my macbook wobble and I could see the interior part of the battery from the outside.
Here is the 3rd battery ~1month ago, bought on eBay for $47; Original Apple from batch from '07 but had w/ 0 cycles. Yes, it has been calibrated a few times and still has higher capacity (tends to be ~100 to 102, today was higher w/ 103%).