By limiting your time in the sun, avoiding tanning beds, wearing sunglasses, and taking other protective measures, you can reduce your risk of premature aging and skin cancer. When possible, stay out of the sun during the peak hours of UV radiation, generally between 10 a.m. and 4 p.m. Remember that sun damage can still occur on a cool or cloudy day. Also, be careful around reflective surfaces like water, snow, sand, and concrete. Such materials can cause a certain amount of UV light to bounce off and reach you, even when you're in the shade. When temperatures allow, guard your skin by wearing long sleeves, long pants, and hats. On exposed skin, apply a good sunblock daily, all year long. Areas like the face, hands, neck, chest, and ears are especially vulnerable. However, keep in mind that sunlight can also get through some clothing, so if you're wearing a thin fabric, you may need to protect the skin underneath with sunblock as well. The best sunscreens are those which guard against the greatest percentage of UVA (U-V-A) and UVB (U-V-B) rays. Look for formulations with an SPF of 15 or higher and UVA-fighting ingredients like titanium dioxide (ty-TAYN-ee-um dye-AWK-syde), zinc oxide, and avobenzone (av-oh-BEHN-zone). Use generous amounts and re-apply after sweating, swimming, or prolonged exposure.