Despite all we know about how to prevent skin cancer, a new report from the Centers for Disease Control and Prevention shows more and more American adults are getting sunburns.

But just five burns in your life can double your risk of skin cancer. Here's what every sun-worshipper needs to know.

Everyone loves a day at the beach, but not everyone knows how to protect themselves from the sun.

It's no surprise that skin cancer is the most common cancer, and rates keep going up.

"No tan is safe," said Dr. Michelle Pelle, dermatologist. "Every time you're sun exposed, you're damaging DNA, you're damaging the skin."

But most people have no idea how much sunscreen to apply. The answer: about a shot-glass full for exposed skin.

And what should you look for in a sunscreen? All brands work the same, though some with zinc or titanium are better for sensitive skin. Do look for UVA and UVB protection?

"If both of these aren't on there, you shouldn't buy the product," said Pelle.

What about SPF? SPF tells you how long you can go without burning.

"If they're going outside for more than 20 minutes, they really ought to be thinking in terms of SPF 30," said Pelle.

A pill can also protect your skin. A pill made of fern plant extract is available over the counter. Clothes with SPF are also a good option. So, whatever your reason for avoiding the sun, protecting yourself is easier than ever.

Sunscreens typically last about three years, but Pelle says there's no reason they should be sitting on your shelf for that long.