Every hour of unprotected time in the sun can provide sufficient cumulative damage to destroy collagen, damage and age your skin, and raises your chances of contracting skin cancer. Also the sun will intensify dark marks, discolorations or uneven skin tone and make them more difficult to get rid of. The ABCs of a healthy complexion start with UV—UV protection. When it comes to keeping a youthful glow, the best offense is a good defense—and that means keeping the sun’s harmful rays at bay, even when there’s no beach in sight.