20 - 30 Minuten
My iPhone 3GS is still working like new, after a few years of intensive use, I needed only a new battery. I have been using iFixit to update and repair our Macs at home following your manuals to do all king of updates and repairs, those repairs were always very easy to accomplish.
As soon as I got the battery and the tools, I logged into the IFixit manuals and I finished the job in 30 minutes. The manual said that it could be done in 15 minutes, but I don't see how.
Your step by step manual and your new video with great information, was enough to help me to get the old battery out. If you follow the step by step instructions anything can be repair.
Repairing equipment that still could work well with a simple update is good for the environment, for our pockets, and it's also fun.