10 Skin Cancer Mistakes Even Smart Women Make

4. All-Day Sun Protection

The Mistake: You always wear sunscreen, so you can stay in the sun all day long.

Even the best sunscreens don't offer complete protection. "Some rays still get through," says Robin Ashinoff, MD, medical director at Hackensack University Medical Center in New Jersey.

Pro Tips

• If you're going to be outside for more than a few hours, wear a wide-brimmed hat and seek as much shade as possible -- particularly from 10 a.m. to 4 p.m., when the sun's rays are strongest.
• Apply more sunscreen every two hours, since the active ingredients start to degrade after that, says Darrell Rigel, MD, clinical professor of dermatology at New York University Medical Center.
• After four hours, two-thirds of your protection will be gone. If you go for a swim or work up a sweat, you need to be even more vigilant about shielding your skin from the sun. The American Cancer Society advises reapplying sunscreen after swimming or perspiring heavily.