When I bought my iPhone 5 (at launch day in Canada) I didn't notice till a month later that there was a manufacturing flaw which was one of the screws wasn't screwed flush with the bottom of the phone. It was a very minor flaw that, on the whole, one could live with. However you would notice it every time you ran your finger along the bottom. It of course wasn't an issue until I bought the app Cycloramic. When in use my phone would wobble and tilt over due to the uneven bottom. Here's the thing, I actually went into the Apple store and they tightened the screw for me. I of course got a minor lecture from one of he geniuses that I should have made an appointment, but they would graciously do it for me. However, just in case, I didn't want it to come loose hence my need to liberate my phone.
It took me all of 3 min. to complete the swap! I spent less time swapping the screws myself than I did waiting for those "geniuses" to fix the flaw. This doesn't even rate on the difficulty scale it was so easy.
Get the kit if you haven't yet. If you ever need to do any repairs/mods to your phone it's best that it has screws that require a readily available screwdriver (philips head) not some weird pentalobe driver. Swapping screws is EASY as long as you know how to hold a screwdriver.