5 - 30 minutos
Original iPhone 4 battery started expanding (actually growing in size) and wasn't holding a charge and also causing phone to die without notice.
The iPhone's screen had cracked, but not from being dropped or misusage, just cracked while in a jacket pocket. Thought it was because I had used cheap glass (on a previous repair) but as time went on I started having battery issues. Original iPhone 4 battery started expanding (actually growing in size...see photo...new iFixit battery on left, original Apple iPhone battery on right) and wasn't holding a charge and also causing phone to die without notice. I also noticed the back glass was being pushed away from the frame. Even though I have taken this same iPhone apart before (to replace a broken front screen) this time I used iFixits guide and thought it was much better than the guide I had used that I found on YouTube by someone else.
iFixit's replacement battery looked EXACTLY like the original Apple battery. Very impressed.