Dropping your iPod isn't a good idea...
15 minutes - 1 hour
I dropped my iPod on the kitchen floor. Even though it's in a silicone protective case, that wasn't enough protection to keep the LCD screen from getting cracked. The iPod still worked, but you could not see what you were doing on the display.
The repair was easy and fast. Plus since I was going to be inside my iPod, I decided to also replace the battery as well. Now my iPod 4G is better than new, and ready for years of use.
Truly the hardest part was snapping the case back together again, that actually took longer then getting it open. My trick was to place it face down and evenly push it back together otherwise it wanted to snap a whole side or corner first which seemed to make it harder to close.