If there's one thing our mothers have taught us, it's that our shiny, full hair and wrinkle-free skin won't last forever (if we had a dollar for every time we've been reminded not to forget the neck...). And while aging isn't a bad thing, you can bet your butts we're pretty damn interested in how exactly these changes will manifest — and what we can do to make the transition a bit more graceful. So we tapped Manhattan dermatologist Francesca Fusco , MD, to get the skinny on how and why skin and hair changes with age.Aging's effects on the skin are widely known at this point, but we still occasionally fall into the trap of thinking we're too young to worry about the crow's feet that could appear in a decade or so. "The changes you'll tend to see [as you age] are dullness; the appearance of brown spots, lines, and wrinkles; and thinner skin," says Dr. Fusco, but she adds that she's seen patients as young as 26 with sun damage and wrinkles, due to a combination of genetics and environmental stressors. Environmental factors, unlike naturally occurring collagen and elasticity loss, are things like smoke, pollution, and excessive sun exposure (moms who sunbathed with baby oil, we're looking at you), which lead to broken blood vessels, patches of dry skin, and sun spots. Basically, if you're alive in 2016, and especially if you live in a big city or a sunny locale, you should start taking better care of your skin now to minimize the effects down the line.Dr. Fusco's first line of defense is always SPF , applied everywhere and whenever your skin is exposed to the sun. "For a day at the beach or at the pool, you should be applying sunscreen every two hours," she says. For your a.m. skin-care routine, she suggests investing in a vitamin C serum ; for nighttime, an over-the-counter retinol (UV protection during the day is a must when using retinoids, which make your skin especially sun-sensitive). "Vitamin C is an antioxidant that has proven to be helpful in fighting the effects of sun damage, the appearance of brown spots, and the breakdown of collagen," she says, while retinol is amazing at stimulating collagen, evening skin tone, and slowing down the breakdown of elastic fibers.Those who are already experiencing dullness due to aging, which typically happens with the onset of menopause around the age of 50, can add an exfoliant to their regimen to help their skin look radiant. "The skin is not regenerating itself as quickly as it used to, which causes a buildup of dead skin cells," Dr. Fusco explains. "Dead skin cells contribute to dullness of skin, and if enough accumulate, your skin may not absorb moisturizer as well as it should." The solution: Reach for an exfoliant at least three times a week (although some formulas are gentle enough to be used daily) in the evening, when skin has time to repair itself. Then, layer on the moisture. Dr. Fusco advises clients to use a hydrating hyaluronic acid serum , followed by a heavier moisturizer that's right for your skin type A less publicized effect of the aging process is the toll it takes on your hair — and it's beyond just going gray. "Your hair may thin, if you're genetically disposed to that. You may get a recession in your hair," Dr. Fusco explains. But the reason your strands will tend to look different has more to do with the scalp itself, which gets drier over time, resulting in a brittle texture all over.Hair-aging might actually be a lot easier to prevent than skin-aging, as your use of hot tools and products play a big role. "Someone who is blowdrying or flat-ironing every day or using a lot of chemicals may see breakage that manifests itself as shorter hairs, or hair that doesn't look as smooth," Dr. Fusco says. That is why older people's hair tends to look a little rougher and less smooth. Heat affects the scalp, and subsequently the hair, so if your scalp continues to get burned, it will compromise the follicle and the hair itself.Luckily, the fix is relatively simple. The easiest thing to do is to use a conditioner — yes, even if you have ultra-thin or fine hair. "You'd be surprised by the number of women who don't use conditioner," Dr. Fusco says. "They're afraid it's going to weigh down their hair." But conditioner keeps your hair healthy — think of it almost like SPF in terms of protection from the elements. Dr. Fusco suggests finding a conditioner that works well for your hair type . And if you find that your scalp is inflamed or irritated due to product buildup or over-drying, find a shampoo and conditioner that are healing or clarifying. "Don't just think it's going to clear up on its own," she says. "Go to a professional and get it diagnosed." In addition, make sure you're wearing a hat when you're outside for extended periods of time to protect your scalp from UV damage.