 Most of us like to be out in the sun. That's why sunscreen and other safety measures are key to protecting your skin from aging and cancer. The FDA recommends using a sunscreen with a sun protection factor, or SPF, of 15 or higher. Also, look for broad spectrum on the label. That means both harmful ultraviolet A and B rays are blocked. UVA rays age the skin, UVB rays burn, and both cause cancer.