While putting on sunscreen is a good thing, women who slather it on and then sunbathe all day end up staying out in the sun up to 39% longer than users who aren't seeking a "healthy tan." And this extra time in the sun may explain why some research has linked sunscreen use to a higher risk of melanoma and other skin cancers. "Using sunscreen doesn't take the place of limiting your exposure to the sun," says Jeffrey S. Dover, M.D., president of the American Society for Dermatologic Surgery. "Although a very high SPF sunscreen may prevent burning, it doesn't provide foolproof protection from the full spectrum of the sun's damaging UV radiation."
What You Should Do: Never bask in the sun—and use 1 ounce (about 2 tablespoons) of sunscreen to adequately cover your entire body. Apply it 30 minutes before going outside and reapply every 2 hours.