10 - 45 minutes
Yikes! My MBP batter bulged so much, I couldn't use the trackpad! It would even rock back & forth on my desk because the battery was trying to get out.
The repair went incredibly smoothly thanks to the iFixit guide & tools. I ordered all the tools I needed for the job and the battery through this site, and it could not have made things easier.
Don't wait! If you notice something, even something small, a bit weird going on with your computer, do some research at iFixit & get it solved asap!