It does seem to be a very personal matter.
So what do you do if you buy a piece online, only to receive it and discover some flaw, like a bend in the blade, where do you draw the line as to, "Well, its a few hundred years old, so I'm ok with the fact that its a little warped/nicked/damaged" and "Uh oh, the seller didnt disclose this, and I dont like pieces that aren't more or less in their original state, plus patina"?