10 - 30 minuten
My iPhone 4s has had battery problems for at least 8 months, if not longer. I tried to limp it along, charging it mid-day, but I'm not always near an outlet. An external battery case was helpful -- but bulky -- and eventually I killed that battery from using it every day. I thought for sure I was going to have to get a new phone, which bummed me out because other than the battery, it still works just fine. And while I'd love and new iPhone 6, I'm frugal. Or is it cheap? Anyway...
The repair process couldn't be any easier. Five minutes later, and my phone was as good as new.
Two things to keep in mind:
One, be careful not to lose the little black grounding tab when you remove the inside screws. I didn't have any trouble here, but I could see where this (and the screws themselves) could be a pain to find if they go flying.
Two, to get the best results once you've installed the battery, I recommend completing a full cycle: fully charge the phone, then use it so that the power drains completely until it's dead. Once you do that, charge and use as normal.