Just after a year the home button on my iphone 4 started to become non-responsive. It worked, but not well. Single taps were registered as triple taps and double taps became elusive. I switched to using my lock/power button to turn on the device from sleeping instead of the home button in an attempt to prolong the life of my home button. After 4 months of increased use of the lock/power button it failed over course of 2 days, changing from a clicky well-behaved button to something that at first functioned but had no click to something that didn't function at all. I had to fix this device.
The repair went fine but I had to use an amalgam of 2 guides, the home button installation and the power/lock button installation. If you are doing both of these jobs, start with the home button installation as it grants greater access to the power/lock button.
After reading several reviews of power/lock button replacement and due to the nature of this button failure I realized that a spacer sitting in between the button and the sensor was missing. I found this spacer stuck in the back of the phone when I removed the back cover. I permanently affixed it to the button with super glue and now everything works.
I found the clip holding the forward facing camera difficult to remove. It has three prongs on it and one is fairly difficult to access. For connector removals I purchased the spudger and the blue plastic opening tools. The opening tools arrived broken but might have made the removal of this clip an easier task.