I have had my iPhone 4 now for a long time. Thinking about upgrading to the iPhone 6 this summer. But then the screen broke after it hit the floor one time to much. Aaa !&&* no. I'm not gonna buy a new phone now, so I decided to fix it.
Repair went very well. It was also my first. I ran into one problem when this one screw didn't come loose and it was the last scew that held the display assembly in place. So I broke the plastic thingy on the old disp.as. and on the new one and made it fit. Haven't got any problem after the repair. And also I think while reassembling the iPhone I also fixed the wifi-problem I've had for a long time. So now I have a new screen and much better wificonnection.
Take your time. And the Screw trays is highly recommended. Reassembling was easy when I knew a exactly where each screw fit.
P2 Pentalobe Screwdriver iPhone
iPhone 4 LCD Screen and Digitizer (GSM/AT&T)
iPhone 4 Home Button Assembly