1 - 2 horas
The lock button no longer worked. Could no longer power down. Wife not happy about that.
It was a success, works great now! It took a LONG time to get everything dissembled and reassembled though. When you are working with ~1mm screws, a heap of patience is needed. I would say I spent close to three hours on this repair. If you factor in tools and my "usual" hourly rate, I didn't save any money fixing it myself. Anyone that says it was "EASY!" must be a neurosurgeon.
The guide posted on iFixit it great, but still you are going have a tough time peeling ribbon cable off and then trying to remember exactly how they go back together. Remember to go slow, make sure you are lining things up/ double checking everything before you go to the next step.
P2 Pentalobe Screwdriver iPhone
iPhone 4 (GSM/AT&T) Power and Sensor Cable