15 - 30 minutes
Crappy battery life on my 1.5 year old 4S. There was some talk about the current ios being a power drain. I tried all the remedial software steps to no avail. Decided to try a new battery.
Went fine! I had the expected problem with the little black grounding clip but was prepared to deal with it. The photos were soooo helpful!
It works! Battery life better and a fine sense of accomplishment :-) Might be nice to describe or photograph in detail how that black grounding clip is supposed to sit. The screws are really tiny.