I can't tell you how often My DS has fallen--whether I dropped it or some bizarre combination of gravity and kinetic energy forced it to the ground. At one point, my L trigger was messed up and didn't work properly. (Same thing happened to my GBA SP, triggers messed up. I was sad... then got a Micro.) This was a major bummer because I was playing Lost Magic at the time, and the L trigger is an integral part of the game.

It seemed to fix itself after a while, oddly enough. I was going to take it apart, and I still might.

Screen protectors should not be neccessary. They're a lot of hassle to actually put on the screen, and if you don't do it correctly you're stuck with ugly air pockets. I suppose they could be good if you really can't help pressing hard on the screen, but otherwise it seems to change the texture of the screen.