25 minutos - 1 hora
My phone would not stay off. When shutting it down it would just reset instead. It would also run out of battery in about 20 hours with no use. It turns out that I had a defective dock connector (no physical damage) that made my phone think that it was always plugged in.
It involved a few small ribbon cables and very tiny parts so I would put it in the moderate area of difficulty. The part worked unlike a couple I had ordered previously off a particular online auction site (the mic didn't work on either of them).
Make sure you have the right screwdrivers, a plastic pry tool, and a nice pair of electronic tweezers. Be very careful with the ribbon cables and take your time. The mic can be a particular pain to re-assemble since it requires you to force a "U" bend into the ribbon cable so it lines up correctly. I used a plastic stylus tip to push the cable into place. Once its in place, the adhesive on the bottom of the board will hold it there. You can then push the rubber microphone casing into its slot using tweezers.