Usually they're self-inflicted since I'm not in a band and I don't gig. I do have a couple of old beaters that were damaged by my brother when we were younger, and I've had a few knocked off stands by other people and animals in the past. Of course, my Axis is in pristine condition, and I plan to keep it that way as long as I can. It hasn't seen a stand and probably never will, so all the dings will be my fault.
My musicman is pretty ding free, most of it's damages are just simple wear from playing it so much, and I'm proud of every single smudge and bit of worn off chrome. I've always thought well used guitars (like SRV or Steve Morse's #1s for example) look great, but it has to come naturally. The who relicing thing is rediculous in my book. The wear should tell a story.
From the ding fairy. Sometimes it's perfect when I put it way away in the case? and the next day when I take it out? it has a new ding on it. Mamma said I should get a new case for it, but I really don't mind the dings much.
My musicman guitars are still mint...but as for my non-musicman family, I'd say 96% were my fault. 1% may have ben caused by "the other guy", and 3% caused by children and pets. (In all cases, my fault for letting "the other guy", children and pets anywhere near my guitars....so really, 100% my fault!)