Tile floors and Iphone displays should never meet, ever.
I was out with my bf getting him his a new smartphone, and flipped my Iphone 4 over to show him something on it, and it flipped right out of my hand, bounced off a counter, and landed display side down on a tile floor 3 feet below. Needless to say something had to give, and it was the glass of the display. End result, he gets a shiney new phone, and I walk out of the store with packing tape holding the shattered remains of my display in place.
The repair went very smoothly. Took about an hour and a half, mostly due to the fact that I was wearing nitrile gloves that were a size to large.
I had printed off the page from Ifixit.com for all my screws, and used my double sided tape runner from scrapbooking to put a sticky spot in each circle so as to not have any screws go missing.
I also had the step by step guide pulled up on my computer right next to my repair area so I could enlarge the pics and double check to make sure that I was removing the correct screw.
Print off the step by step before starting. The power went out just as I was about to begin, and had to wait an hour for it to come back on to start my repair. Thunderstorms are evil. Also, if you print it, and you print one step a page, as you complete the step flip the page... then to reassemble you just work back through the pile.
If you print in black and white, read through and then mark on your pages where Ifixit.com had screws labeled with colours. I ended up just looking at my computer screen and clicking on the smaller photo, but it would have saved me some time if I had done this instead of having to find the step online.
I also used my camera to take video reminders about things that I had to watch out for (the back camera had a part that tucks in, and the ribbon connector threads through here ect.) when reassembling.