20 - 30 minutes
Wife's 3GS: battery was draining out in half a day
I saw the video, looked at the steps carefully. It still took me 30+ mins, but glad everything worked out in the end, without having to re-do anything.
1. First of, things are a bit tiny in general, so fresh pair of eyes (morning) is better :).
2. To ifixit team: please post a pic after unwiring the #3 ribbon. It was a bit difficult to understand which tab to flip up.
3. The "do not remove" tape never came out in 1-piece - there were many pieces. So during re-install, I cut a see-though-tape of same size and using a tweezer (yes wife's tweezer) put it on screw-6, where the 'do not remote' original tape was.
4. At same place, when installing the main logic board, the ribbon near/top of screw-6 needed to be placed correctly so that the little copper connector (grounding or antenna?) from teh board touches the external shell correctly. That is key to good signal I think.
All else was good. Happy I did it the first time around. The new battery showed 55% capacity when first powered, so I let it drain out completely before 1st full charge. The new battery lasted closed to 1.5days (compared to .5 on teh old one - very happy!).
BTW, if at all it matters, the 3GS was already running IOS5.0.1 before battery upgrade - and reporting no issues.
A big thanks to ifixit! Great work there. I look forward to extending hte life of my iphone4 when the time comes (instead of always looking to upgrade).
PN from San Jose, CA