I've bought a few used guns and reloading equipment, over the years, that had obvious problems that often previous owners created and just passed along. None of the problems were of a catastrophic nature and I was able to resolve them without too much trouble and expense. I never had that with people I know well. I am not a big fan of passing along problems that I know about and when possible, I'll correct them prior to a sale or make the problem know to a potential buyer. I've bought a new product and had trouble with it and got a new replacement. When I've done that and sold the brand new one, I feel compelled to tell the buyer of the previous problem(s) with the other (returned) one. At gun shows there are a lot of used problem items for sale. That is where "caveat emptor" really has a meaning, but sometimes, no matter how carefully you inspect something, there is always a possibility that it is a lemon. I've even seen bad ammo being hawked and have fallen victim, as well as, my buddy. I guess my advice is when buying stuff, research it and try to stay within your scope of knowledge. You still may get burned, I have, but less often.