30 minutes - 2 heures
My iPhone 4s was in a bag along with a water bottle that leaked. The phone was soaked and after drying, the camera flash would not turn off and the vibrate switch would no longer function.
The camera was a breeze. The vibrate switch a little more challenging: you have to take most of the phone apart to get to it. But the guides were great, and while at first I thought the magnetic project mat a little overkill, it's really quite handy.
The phone started right up when I reassembled it. The camera worked and the flash no longer stayed on. The vibrate switch still didn't work, however. I saw a lot of water damage / corrosion on the motherboard right around where the vibrate / volume cable plugs in, so the problem is likely on the motherboard.
Pay close attention to the part about prying the microphone away from the case. I had the directions printed so I didn't see the close-up image and ended up forgetting about it and tearing the cable. Luckily the whole point was to replace the cable so it didn't matter.
iPhone 4S Rear Camera
iPhone 4S Headphone Jack & Volume Control Cable
Magnetic Project Mat
Pro Tech Toolkit