Unless you've been living under a rock, you know to apply sunscreen. There's a lifesaving reason to: About 3.5 million cases of skin cancer will be diagnosed this year. “The incidence of skin cancer, including melanoma—the deadliest kind—is going up, and wearing sunscreen is one of the best ways to prevent it,” said Dr. Ronald Moy, a dermatologist and spokesperson for the Skin Cancer Foundation. Stick with these smart tips—and check out our product picks—to make sure you're as protected as you can possibly be. Select a sunscreen you love Finding your sunscreen soul mate is the key motivating factor for using it regularly, experts agree. “If you think your sunscreen is pasty, thick or smelly, you have the wrong kind,” said Dr. Jeffrey Dover, clinical associate professor of dermatology at Yale University. “It may make you less likely to put it on, or to reapply when you do.” Happily, there are plenty of lightweight, sheer formulas, like Vichy Capital Soleil Foaming lotion SPF 50 ($29; vichyusa.com) and La Roche-Posay Anthelios 60 Ultra Light sunscreen fluid for face SPF 60 with Cell-Ox Shield XL ($30; laroche-posay.us). Health.com: Which Sunscreen Is Best For You? Remember, SPF 30 is the new 15 As a general rule, SPF 15 blocks 93 percent of UVB rays, SPF 30 blocks 97 percent and SPF 50 blocks 98 percent. Doctors now typically recommend at least SPF 30—at least being the key words. If you have a family history of skin cancer or are vacationing in a tropical spot (where the sun is especially intense), go for 50 or even 70. Just keep in mind: No sunscreen provides 100 percent protection. So to be as safe as possible, you still need to reapply every two hours and after a swim, even if you used the water-resistant kind, said Dr. Joshua Zeichner, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City. Try Neutrogena Beach Defense sunscreen spray broad-spectrum SPF 30 ($11; at mass retailers). FYI, sunscreen becomes less effective about three years after you open the container. Check labels for the term broad-spectrum It means the sunscreen provides protection against both UVA (wrinkle- and cancer-causing) and UVB (burning) rays. Problem is, that labeling rule only went into effect in December and stores still sell inventory made prior to it, noted Dr. Steven Wang, director of dermatologic surgery and dermatology at Memorial Sloan-Kettering Cancer Center in Basking Ridge, N.J.  So if you're shopping and there's no broad-spectrum mention, check the ingredients for zinc or avobenzone, the only two that provide top-notch UVA coverage, he says. Coola Mineral Sport broad-spectrum SPF 35 Citrus Mimosa ($36; coolasuncare.com) contains zinc, and L'Oréal Paris Sublime Sun Liquid Silk Sunshield for face broad-spectrum SPF 30 ($10; at mass retailers) has avobenzone. Health.com: 7 Ways You're Aging Your Skin Layer it on Think you apply enough