1 - 3 hours
LCD had a large 'dead' area. Usable but ugly.
Intense but successful. Suggestions on keeping parts organized were VERY helpful. In the 'iPhone4_Display_ReplacementGuide.pdf picture for step 18 (Lift the grounding clip) confused me. I keep trying to pull the shiny part (under the thumb).
Print out the guide BUT realize all the pictures don't print. Use that as your guide, tracking and checking off steps so you can retrace more easily. HEADLAMP and, if needed, reading or magnifying glasses. A Headlamp (like a camping type or ones you get a HomeDepot) was critical. Take your time and pray (I'm not kidding!). Took me about 4 hours (20 minutes on step 18), BUT IT IS NOT A TIMED COMPETITION!! The satisfaction from saving/re-using an existing phone is a great part of the reward.