The thought of washing your face at night can sometimes be as appealing as curling up with a textbook. And TBH, you’re not even wearing a lot of makeup so what’s the point, right? Wrong.

Your day-old makeup — plus the sweat and oil that naturally accumulate throughout the day and the pollution and grime from the environment — is standing between you and the complexion of your dreams. It might even be prematurely aging your skin.

“Your skin is your biggest organ, and it must be tended to,” says Janet Pardo, senior vice president of product development for Clinique. David Orentreich, M.D., a dermatologist also with Clinique, agrees.

“Your skin is constantly working 24 hours a day,” he says. What's keeping it so busy? During the day, your skin is in protection mode — keeping your complexion free from harmful rays and free radicals.

At night, your skin goes into repair mode — creating healthy cells, regenerating levels of collagen, and more. By sleeping in your makeup, your skin has to work way harder to get through all that dirt and grime.

Still not convinced? Read on before you decide to face-plant into your pillow.

1. Your Pores Will Be Pissed

Anyone who’s ever examined their skin in a magnifying mirror will agree: Clogged, oversized pores do not a radiant complexion make. Adding to this problem? Unremoved makeup, which is embedding itself into your pores. “Makeup can actually stretch the pore and make it look bigger,” says Dr. Orentreich. By removing your makeup and cleansing your skin, you're giving those poor pores a chance to stay clean and healthy.

You don't need a complicated skincare regimen for glowing skin, a simple routine totally suffices. Focus on the fundamentals: cleansing to remove debris, exfoliating to shed old skin cells and encourage cell renewal), and moisturizing to balance oil and water levels in the skin.

Try the Clinique 3-Step Skin Care System, which covers all the basics you need to get your skin to a healthy place. Gina Mari, a Los Angeles-based aesthetician, notes: “Anytime you’re not taking care of your skin, you’re contributing to clogged pores. I would not want to be that pillowcase. You’re taking Monday into Tuesday into Wednesday.” Which leads us to…

2. Your Skin Will Get Dry

The makeup that felt so fresh this morning? Yeah, it's basically a moisture-sucking machine by nighttime. Removing it gives your skin the chance to breath and recalibrate its moisture levels. “The first job of the uppermost layer of skin, the stratum corneum, is to lock your own moisture in and maintain the skin’s natural moisturizing factors," says Mari. It's this ideal balance of oil and water that makes your skin feel comfortable. It also helps keep the good stuff in and the bad stuff out, says Pardo. By applying a moisturizer, like the Clinique Dramatically Different Lotion , $26, clinique.com, post-cleansing, you help to restore this ratio.

3. You'll Bring Pollution to Bed

No surprise here — it's a dirty world out there. Particles from car exhaust, smoke, and industrial pollution gather onto your skin throughout the day. If you don’t get them off, this chain reaction of oxidative stress (like pre-mature aging and increased sensitivity) continues right on through the night. Sure, some parts of the country are less polluted than others, but still, “it’s one earth,” says Pardo. “The winds blow and eventually it gets everywhere.” Interestingly, makeup can actually absorb some of these particles, as can sunscreen. Even more of a reason to wash it all away before you get into bed.

4. You'll Basically Be Staging Zit-apalooza

The perfect recipe for acne? The aforementioned buildup of bacteria, debris, and oil. Even if you're not normally acne-prone, you'll soon find that sleeping with a face full of makeup will result in heinous breakouts. The occasional "I'm sooooo exhausted" night won't lead to a full-blown situation, but over time, your skin won't be able to turn cells over like it's supposed to. If you're dealing with regular breakouts and want a cleanser that removes makeup and helps clear acne, try a gentle foaming formula like Clinique Acne Solutions Cleansing Foam, $20, clinique.com.

5. Your Skin Will Get Irritated

Think about all the places you and your makeup have been today. Then imagine it hanging around all night. If that sounds like a recipe for a flare-up, it's because it is. “The skin is good at tolerating a lot of things, but it can become reactive. You don’t want to leave things on longer than you have to,” says Dr. Orentreich.

So makeup that might be fine for eight hours can actually create a negative reaction in your skin when left on the skin for 24 hours, he adds. And if you're already prone to sensitivity, sleeping with makeup can trigger skin issues.

Like with acne, it just goes back to finding a cleanser suited to your skin type. If you have sensitive or even rosacea or eczema-prone skin, look for skincare formulas that are fragrance-free; oftentimes, the fragrance offers no additional benefit. Ditto with choosing oil-free formulas if you tend to be on the oilier side.

Now go to bed!