The sun is your skin's arch enemy. Even in the wintertime, when you may not feel the heat of the sun, those dangerous rays are just as harmful. Over time, UVA and UVB rays break down the collagen in the dermis, leaving you with wrinkly, tough skin. Moreover, skin cancer in the United States is on the rise, especially among women under 40 [source: Healy]. For that reason, using a daily body moisturizer and sunscreen combo is the smart way to go. In order to block both A and B types of ultraviolet radiation, check labels for more that just SPF. An SPF of at least 15 will protect against UVA rays, and you'll also want the lotion to contain zinc oxide, octinoxate or oxybenzone for additional UVB defense [source: Lyon]. Preventative care like this is essential for maintaining healthy skin in the long run because once sun damage sets in, you can't turn back the clock.