2 - 3 uren
Had problems with both dock connector and, apparently, power cable. Phone was turning back on by itself and swapping audio output modes randomly. Also couldn't put phone to sleep using power button and if the phone was off, couldn't turn it on with button (had to plug into charger to turn on). Replaced dock connector first and that solved some but not all issues. Replaced power cable and that solved my issues.
This went fairly fast because I had already removed and replaced dock connector twice (first one from iFixit was defective). But it's definitely a difficult replacement. In particular, the last step of removing the power cable was tricky because the photos and instructions don't provide sufficient detail for you to know how the part disconnects.
Slow and steady. I'd suggest keeping track of all the little screws by location rather than trying to differentiate a 1.3mm screw from a 1.4mm screw. Some screws are fatter than others and I tried to insert those first since it was clear whether or not they'd fit in the hole.
Lastly, the less expensive #000 screwdriver isn't very durable. The tip will wear away and then it won't seat tightly in the screw head. I bought the liberation kit and ended up using the cheapo screwdriver that came with that fro most of the repair. It held up better than #000.