15 minutes - 1 hour
my iPhone 5 battery rapidly lost charge and even the phone even started to shut down even though it showed 40% available. Apple wanted $100 and I had to send it in the mail!
The repair was certainly tricky but with patience I got it done. I did seem to end up with a loose wire somehow, but the phone is fully functional so not sure what that was about.
I skipped the step to remove the front panel since I don't think it's necessary as long as you're careful.
The screws are TINY so make sure you do it on a clean surface. I thought I lost one screw and it took an age to find.
Finally - one of my screws wasn't magnetic. Keep a pair of tweezers handy if this is the case for you.It will help you to drop the screw back in place.