If you’re like a whopping 50 percent of the under-30 population, you got sunburned sometime this year, according to a 2012 report by the Centers for Disease Control and Prevention. But even if your tomato-red color has faded and your skin has stopped peeling, the effects of that burn are far from gone.

No, you can’t develop skin cancer within one summer season: “It takes about five-plus years once you do the damage for you to see it, even 10 or 20 years sometimes,” says Darrell Rigel, M.D., a board-certified dermatologist and member of the American Academy of Dermatology (AAD). “It takes years for the spot to get big enough to be seen.” But it’s still worth doing a quick body scan to see if any new spots have popped up, while sun and skin are on your mind. (It’s all too easy to forget about it when you’re bundled up in sweaters). Better yet, make the end of summer an excuse to head straight to your derm for an annual checkup. (Here’s everything you need to know about skin cancer screenings.)

Why? A new study published in the Journal of the American Academy of Dermatology found that, when it comes to skin cancer risk, new spots are much more dangerous than existing spots. Researchers looked at 38 studies comprising 20,126 melanomas and found that less than one-third (29 percent) of melanomas (the deadliest form of skin cancer) arose from an existing mole, while the vast majority (71 percent) appeared on the skin as new spots. (And it’s not just melanomas you should worry about. Non-melanoma skin cancer rates are rising rapidly.)

“So you won’t find what happened this summer,” says Dr. Rigel. “But if you have a habit of being out in the sun in prior years, this is a good time to get checked and see what’s going on.”

And even if you’re looking for spots yourself, a derm (with a highly trained eye) will be able to notice things that you may not see as a threat. “Skin cancer can be hard to detect, but dermatologists are trained to do exactly that,” he says. This is extra important because “early detection is absolutely critical,” he says. “With melanoma, if you catch something early, it’s no big deal, but once the melanoma spreads, almost nothing works.”

If you see a new spot and it (or an old spot) is growing, crusting, bleeding, or changing, go see your dermatologist, stat. Regardless of whether you spy anything questionable, you should be getting a yearly skin check as part of your routine wellness exams.

“Once a year, get your skin checked. Learn your skin, learn your spots,” he says. It’ll only take five minutes, and you can rest easier knowing that you’re covered: “At the end of the day, the bottom line is to be protected,” he says. And yes, that means year-round.