Sunscreen is the absolute BEST thing you can do for your skin. It's the most important step of any skincare routine, and it mortifies me to think I didn't used to use it daily. Since active ingredients can promote faster cell turnover, you need to make sure your fresh skin is protected. I like Neutrogena Clear Face Liquid-Lotion Sunscreen SPF 55 ($13) because it doesn't make me too shiny and my makeup goes over it nicely.