"Incidental sun exposure (the little bits of sun we get) while walking, driving, etc., build up over the years," says Bank. He recommends applying SPF 15 daily. If you plan on getting more sun exposure, wear SPF 30 and reapply every two hours. See the sunscreens our readers love and hate here. "And don't be fooled into thinking that your clothing acts as sun protection," says Kunin, adding that our clothes only provide an SPF 4. Protecting your skin from the sun daily will help prevent premature aging (think brown spots and fine lines) and skin cancer. One other bit of wisdom: "protect your eyes with real UVA and UVB sunglasses," says Kunin. "The sun can cause cataracts, blindness and even melanoma."

"At night is when all of your skin rejuvenation happens," says Lorencin. If you wear makeup to bed your skin can't get the oxygen it needs. When skin is suffocated, "your natural collagen building process is compromised," she says. Kunin adds, "it will also clog pores and act as food for bacteria," which can cause breakouts and make pores more visible. In addition, if you don't wash your face at night, you're not doing anything to fight aging, combat pimples or treat other skin issues since you're not exfoliating or adding beneficial spot treatments or moisturizers.

Check out some of our readers' favorite makeup removers here.

Getting a complete skin exam once a year is essential to your overall health because it can help prevent serious issues, like skin cancer. "There are so many spots that are hidden," says Kunin, explaining why getting your moles checked by a doctor is so important. "A large number of abnormal things can be picked up instantly," she says. If you do see a suspicious-looking spot or mole, don't wait until your yearly exam, see a doctor sooner to make sure you're in the clear.

"When your body is stressed, it pours out a stress hormone called cortisol," says Bank. This causes a multitude of things. "It robs the skin of its blood supply and can elevate blood sugar, which can cause cells to function abnormally," says Bank. It can also affect acne oil glands. So bottom line, when you stress out your skin may be more prone to breakouts and is likely to look dull and sallow. Bank recommends finding a stress-reducing activity that works for you. Whether you choose deep breathing, yoga, walking, "even 15 minutes can make a difference," says Bank.

Try one of these stress-reducing, skin-benefiting DIY beauty recipes to help you unwind.

"There is no way you can look great if you are sleep deprived," says Lorencin. And though Bank admits, "we don't fully understand sleep and the complex biochemical things that go on during it," he adds that whatever is going on is critical. When your body is fighting to say awake "muscle tone relaxes so you look saggy, blood pressure drops which robs skin of color and you're prone to puffiness due to poor circulation," he says. Yet more reasons to get the recommended seven to eight hours of sleep a night.