Any change in skin color indicates sun damage — and yes, that means freckles, too. "The first freckle you get, even as a child, is an indication that your skin is aging," says Mona Gohara, associate clinical professor of dermatology at Yale School of Medicine. Talk about scary. Anytime you notice spots start to crop up, especially if it's earlier than your late 20s when most people will start to see them, consider it a major sign to up your sunscreen game ASAP, says Arch. (FYI, they usually first appear on the left side of the face—blame UV rays coming in the driver's side window—as well as on your hands, notes Gohara.) To fade existing discoloration, look for a treatment with ingredients such as vitamin C, licorice, niacinamide and/or retinol (try: Neutrogena Rapid Tone Repair Dark Spot Corrector, $17.96). And, of course, WEAR. SUNSCREEN. EVERYDAY.

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While noticing a few crinkles around your eyes when you laugh or a few on your forehead when you furrow your brow is one thing, but take note if they appear even when you're not moving your face. "Seeing deeper, etched in lines on your forehead or around your eyes in your early to mid-20s is a little early," notes Arch. Injectable neuromodulators (think Botox) are an option, but topically, your best bet is a collagen-boosting retinoid (try: CeraVe Skin Renewing Cream Serum, $16.99). Minimizing stress can also help since cortisol (the hormone released when you're stressed) breaks down collagen and elastin.

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Diffuse, persistent redness can indicate that you have broken capillaries, says Arch, who notes that this typically shows up on the cheeks and around the nose. The culprit? You guessed it: sun exposure. The earlier you see these, the worse. As if you needed it, consider this yet another reason to slather on SPF on the reg.

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"Laxity typically doesn't show up until you're in your 40s," points out Gohara, so if you're starting to see saggy skin before then (it'll first show up along the jawline), that's considered early. "Sun damage first causes superficial discoloration, then damages the collagen and elastin in the lower layers of the skin, causing this droopiness," she adds. Besides using sunscreen (shocker), look for an anti-aging treatment with peptides, which can help stimulate collagen production for stronger, healthier skin. We're fans of the new Drunk Elephant Protini Polypeptide Cream, $68.

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Persistent, chronically dry skin typically occurs when women start to undergo hormonal changes in their late 40s and early 50s. Before then, it can be a sign that your skin is simply aging faster than normal. But don't blame yourself: This is one issue that has more to do with the genetic cards you were dealt than any kind of lifestyle choices, notes Gohara. Since this kind of dryness is typically correlated with lower levels of natural hyaluronic acid, load up on a product that contains it (try: Derma E Hydrating Serum, $29.50). Layer under your moisturizer day and night to help keep skin healthy and hydrated (and youthful).

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