5 - 30 minutos
The home button on my iPhone 4 was unreliable, and while I'd upgraded to the iPhone 5, I wanted to see if I could fix it. I replaced the battery while I was at it.
I did run into trouble with this repair. On step 13, when removing the wi-fi antenna, I couldn't unscrew the 1.4mm screw. Upon closer inspection, I discovered that the part it screws into was not attached to anything, and was rotating freely. I wound up going to my local Micro Center and picking up a pair of ultra-fine-point tweezers, with which I was able to get a grip on the recalcitrant part and unscrew the screw. Once I did that, the rest of the repair went without incident.
The whole project took me about six hours, not including the time spent shopping for tweezers.
When you run into trouble, stop and think. Sleep on it, if necessary.
Also, I would have been happier if I'd had two sets of plastic opening tools.
iPhone 4 Replacement Battery
iPhone 4 Home Button Assembly