Many many times. Collectors sometimes want a gallery print signed. I guess it makes it more valuable sometimes? And people who buy books and magazines frequently enjoy having the creator or a contributor sign them, so I've been asked about a zillion times to sign things I have written or edited. Not enough times that I've ever been bothered and said no though
Actually, I don't know why I feel like I have to explain it. I think I've signed a lot of autographs for someone who is not a public figure and none compared to Kiss.