5 - 30 Minuten
My wife's iPhone 4 seemed to be suffering from a defective battery for quite some time. We shrugged off its inconsistent performance, thinking it would sort itself out with a little time.
After discovering that her phone went from 100% to 14% in just four hours, after doing little more than texting and periodically browsing a favorite app, I decided enough was enough. And besides, replacing a battery is a ridiculously easy fix.
Ridiculously easy! That is--once I managed to obtain the proper driver for the task. During my initial attempt, I found out that, unlike my iPhone, my wife's iPhone had the pentagons screws installed in it. After getting the pentagons driver, it only took about 10-15 minutes to replace the battery. In hindsight, it's a bit comical that a task as simple as replacing a battery for a mobile phone involves any work at all, but leave it to Apple to create a riddle out of something as easy as battery replacement.
Check to see what kind of screws your iPhone has installed on it before you order your supplies (unless you already have all the tools you need). Other than that, just follow the guide! Also, it's a good idea to wash your hands prior to performing the repair, to remove the natural oils from your hands.