The Sleep/Power button on my iPhone 4s suddenly stopped working.
It was a bit tricky keeping track of all the different screw sizes. Took me a good amount of time and focus, as it seemed the switch I was replacing was the first part to go into the phone. This meant I had to take practically everything out of the phone first before I could get to it.
Keep track of all the screws. Be careful not to strip the tiny ones. Work patiently as to not damage the fragile parts inside.