We all know we need sunscreen. Not only does it protect us from skin cancer, it protects against overall sun damage. And as you age you can tell those that constantly wore sunscreen and stayed out of the sun during peak hours, and those that baked. While certain skin types are more susceptible to sun damage than others, you can do a lot to protect yourself. That said -- sunscreen and how it works remains largely a mystery to many of us, according to StyleCaster. 1. UVA and UVB rays are different. UVB rays are the rays of the sun that cause you the pain, meaning they’re what actually causes you to burn. While UVA rays actually cause the sun damage that can cause skin cancer. Protect yourself from both using broad spectrum UVA/UVB protection. 2. SPF has a meaning. SPF stands for Sun Protection Factor and refers to the theoretical amount of time you can stay in the sun without getting sunburned. For example, an SPF of 15 would allow you to stay in the sun 15 times longer than you could without protection. So, if your skin starts to redden in 20 minutes without sun block, applying a product with SPF 15 increases that time by a factor of 15, meaning you could stay in the sun for 300 minutes. In addition, a higher SPF blocks out more rays—a product with an SPF of 15 will filter out approximately 93 percent of UVB rays; SPF 30 filters out about 97 percent. 3. Certain parts of the body get more sun. The parts of your body that are not hidden under shadows get the most sun. Your nose, chest, and the tops of your feet don’t have any shadow, so make sure you protect these parts of the body with extra SPF protection. Sun protection may be more complicated than it seems. It's important that you understand how to protect yourself so that you can avoid skin damage and, worst of all, skin cancer. Sara Novak is a Natural Health Care Expert for Zax Health. Follow her on Twitter at @sarafnovak.