As the weather heats up, so does the talk about sunscreen. Reapply every 2 hours—or every 4 hours. Only use SPF30 or higher…but maybe the SPF15 in your moisturizer is okay. Here, Refine medical director Dr. Jonathan Levy (pictured above) clears up misconceptions about your skin and sunscreen. Learn why SPF80 might not be as protective as you think, which UV rays your sunscreen is blocking, and how to know which brands will make you less likely to break out.