45 minutes - 2 hours
I phone 5 power button became funky. Intermittent, phantom turn off, etc.
The repair instructions were PERFECT. But be warned, you basically have to take 95% of the circuitry out of your phone to do this repair. My repair was 100% successful.
To keep track of the screws, get 6 or so pill bottles and put the screws and the parts for each step into individual pill bottles. The screws appear to be all the same thread (thankfully) but are different lengths. Some vary by only 0.1 mm!
Have good light, a steady hand, and a pair of tweezers.
When putting the display connectors back together, take a small camel hair artists brush and brush the male and female contacts thoroughly to get the dust out. Spray with canned air. These connectors have to be spotless or you get about 4mm of color bars on the top of the screen with flakey touch screen performance.
Go slow, be patient, and don't sneeze! This repair takes some finesse and great care. No forcing things either apart or back together.
iPhone 5 Audio Control and Power Button Cable
iPhone 5 Power and Lock Button
P2 Pentalobe Screwdriver iPhone
iFixit Opening Tool