1 - 2 hours
Glass screen shattered.
I started out trying to just replace the shattered glass screen. That turned out to be an exercise in absolute frustration and insanity. On a scale of 1-to-10 it's a 12 on near impossible. I recommend this if you want any good results in the end process. The only solid repair is to replace the glass screen, digitizer and the metal back (heat shield) with the home button flat cable as complete unit. This will assure you of a 100% success in the repair.
The few advice areas I would strongly recommend:
You must be very patient, relaxed, and careful in the pursuit of the repair.
Order the complete repair kit with the repair item. It comes with the tools needed and it helps greatly.
Make sure that you clean the home button thoroughly with the alcohol wipe that comes with the kit before you reinstall it. This is a must do.
Along with your hands, your work area should be clean and organized with little containers for screws and other parts. You wont believe how tiny the screws are.