5 - 30 minuten
The battery in my iPhone 4 started to discharge faster and faster, to the point that it could not make it thru the night. Thought about using it as an excuse to get a new phone, but then did the adult thing and fixed it. It will eventually go to my wife, or become a fancy iPod, so why not!
The repair guides all over the internet helped a lot. Despite being nervous about screwing up, I forged ahead. Took about 15 minutes, with minor hitches, caused mostly by lack of information and nervousness...
Still watching the new battery to see if it holds a charge the way I want. I'll update as info comes available.
Be sure you know WHICH iPhone you have! The instructions for the ATT iPhone and the Verizon iPhone are slightly different with respect to the antenna/grounding clip (I had to find this out from a different website!).
Be careful taking out the pentalobe screws. If you don't press down it feels like you could strip them pretty easily.
To remove the back takes a little more pressure than I expected. I put on rubber gloves to help me get a grip.
Don't bother pulling the pull tab to remove the battery. Just GENTLY use the spludger to pry the battery out a side at a time (I had a lot of adhesive). This was probably the most worrisome part.
Finally, when you put the battery back in, the battery ribbon is NOT prefolded and you WILL have to do this. I HIGHLY recommend you keep the old battery in front of you as a template and do a dry fit before committing.
DON'T be put off by all of this; it is an EASY repair (and I have replaced batteries and hard drives on old iPods and this is a hundred times easier). I just provide this as a heads up!