Mmm, depending on your skin (and the sunlight) it can get damaged after just 5 minutes exposure. I saw a program once where they got two females who always lay at the beach all day long and tanned, and they ah, examined their skin under some kind of light and it showed the damage done to the under layers- well, when I say damage I mean a whole mass of ugly brown patches that you can't see on the outer layer of skin. And apparantly as they get older those splodges are going to become visible! sorry about the bad explanation but I was fairly young when I watched that and wasn't paying much attention.

When you think about it, a lot of people really don't have suitable skin for the climate that they're in (me for example) because of immigration and all of that. Australia for example- colonized by the english (and a few others, in the beginning). If you compare the difference in skin colour between the Aboriginals and people of European descent... No wonder sunburn and skin cancers are such a problem!