They have a very deadly addiction. I used to tan a lot. It never seemed to be dark enough to me until I moved out here in S.Cali and saw what the sun had done to so many of these people. It totally ruined their skins and aged them horribly. Last year I read of one woman who had lain out in the sun on a tanning blanket. Her neighbor got concerned after seeing her laying there for two days and went to check on her and found her totally cooked. Very creepy. I would say that yes, you sure can tan to much.