20 - 30 minuten
The battery on this 3GS would deplete rapidly after the battery got below 50%. Not the norm for these phones. Our older 3G has a great battery even though it's over three years old.
Went pretty much as shown in the repair guide. Took appx. 30 min. Having done it once, the next one would be a breeze. One thing that would have helped would have been to know just how the last ribbon cable holding the display to the logic board released. I spent some time prying on it different ways before discovering the clamp flips up to release the cable.
A little line drawing of the above mentioned ribbon cable connector or a "clamped" & "unclamped" close-up would have helped me. Also, not to look a gift spudger in the mouth, but it might have been nice to have one end with a more shallow angle. Would have been easier to approach and get under some things, still it worked well for prying the battery up.