I always have wondered. My grandparents and great uncles were in the Texas sun non-stop without any sunscreen for their entire childhoods and adult years, but never got any form of skin cancer.

They worked the farm in the morning and afternoon. When it was the the heat of the day they rested and stayed in the shade. They wore wide brimmed hats and clothes when they were in the sun.

Key: Stay out of the sun during the hottest part of the day.

Then baby boomers and younger generations started slathering on sunscreen and would go out in direct sunlight or even lay in it for hours (for a tan). They all thought they were safe as long as they wore sunscreen. Skin cancer rates exploded.

Key: Stopped worrying about getting hit with direct sunlight because sunscreen will "protect" us.

Many also thought having your entire body tanned from head to toe was healthy. When it's just your forearms and nape getting the most exposure then you just keep a close eye on those parts. Now people tan their entire body to avoid tan lines and have to watch a much greater amount of skin on their body. It makes it harder to spot the early signs of skin cancer when it could be anywhere including the places you rarely look.

I think being smart about your exposure is what's key. People used to be smarter about the sun, but sunscreen gave them a false sense of security.