2 - 5 Minuten
The camera lens got so scratched from rolling around in my bag that I couldn't take pics or video
It was so easy. I took out the old screws, popped off the back and slide my new nifty mirrored back on in a few short minutes.
The pentalobe screws are a bit of a pain to get out. You have to use a little more force than I was expecting to unscrew them.