1 - 2 hours
The power button on my iPhone 4 stopped working unless you pushed it at a weird angle, so I decided to take matters into my own hands
Well, it took longer than expected. A few of the pieces were tricky to fit back together such as the power button and wifi-shield. After a few attempts and making sure the wifi shield was positioned correctly I got it all back together. While holding my breathe I pushed the power button felt a long forgotten click and saw the apple logo light up to my relief.
Make a grid or use a calendar to lay out the parts from each step there are a lot of tiny screws that can easily be messed up.