It's very common and most laptop technicians/repair guys do this. They charge anything from Rs. 2,000 - 3,000 depending on the total no. of cells. As you can see from the video, it's relatively easy to do it yourself but finding the right cells can be a problem. So, getting it done by someone else is not a bad idea, considering new battery backs are VERY expensive. Especially for VAIOs and ThinkPads.