20 - 30 minutos
My Iphone 3GS (18 months old) kept shutting off for no apparent reason, even when it claimed to have 80-90% power left! this was getting extremely frustrating! It would shut off without warning, if i was texting, in a call, loading websites. I spent time "googling" the problem, thinking it was the latest update apple had given had messed it up i tried to persevere until apple released a fix, but the fix did not cure my problem. I was ready to give in and buy a new phone when i came across info on battery problems and in a forum was recommended "ifixit' - Thank Goodness I did!
I followed the info given on the ifixit website step by step, the trickiest bit was pushing the tabs back in after replacing the battery, only because they are so small and delicate. Other than that it was easy. ifixit have given a great guide!
If you follow the ifixit guide step by step and take your time in doing so, you will find it easy enough. Make sure you have the suction cup as recommended to get the screen off, it really does work! I am so happy i took the chance to repair it myself, i have saved a ton of money! thanks ifixit!