I just had my battery replaced yesterday in my 15" MBP. This is the second time in 20 months. The first time was 10 months ago, and they did that for free. I had to buy the battery this time, because they said the first replacement only had a 90 day warranty. I had 135 cycles and only 60% life remaining. The genius told me that 100 cycles a year is normal wear, so I was over-using it. I don't agree, but had no other option but to spend the money. And he did say that they would only replace under warranty if it was under 300 cycles.