Everyone, and I mean everyone, has a bad habit (or three), and even if you’re not the resolution type, making one change this year can do wonders for your health, looks and self-esteem. Here are five common not-so-great habits, and how to break ’em for good.

1. Bad habit: Nail Biting Stop now – Biting your nails makes for ugly hands and over time can interfere with normal nail growth, damage the outer layer of your teeth, and cause nail deformities such as split nails. Harmful bacteria such as staphylococcus also live underneath nails — and you don’t want to chew on that.Break it: Go for a professional manicure once every 2 or 3 weeks, suggests Angelica Kaner, PhD, a clinical professor at Yale University Medical School, because when your nails look pretty, you’ll be less likely to snack on them. At the very least, keep your nails trimmed short — you’ll have less nail to bite, and that harmful bacteria has less space to grow. Nail biting is also a nervous habit that is often an expression of some deeper anxiety. “Ask yourself why you’re feeling anxious,” Kaner says. You can also try substituting a new, healthy behavior — instead of biting your nails, rub in a cuticle cream or oil.
2. Bad habit: Forgetting to Floss – Flossing helps prevent gum disease and keeps your teeth and gums looking good, but it may also stave off non-mouth-related diseases: A 2005 study in the journal Circulation showed that older adults with higher levels of four gum disease-causing bacteria in their mouths also tend to have thicker carotid arteries, which raise the risk of stroke and heart attack. That’s scary business, because 90% of dentists say that most patients don’t floss regularly.Break it: Buy a floss-holding device, such as the Flossmate Floss Holder to make the process easier and faster. In an Indiana University study, 50% of previous nonflossers were doing so regularly 6 months after introducing floss to their routine; 85% of the new flossers used a holding device — only 15% preferred doing without the aid. Then incorporate flossing into your morning routine before or after brushing.
3. Bad habit: Late Night Fridge Raiding – Eating late at night in itself isn’t bad for you, but chances are you’re eating cold pizza instead of apple slices. Adding those extra calories does the late-night damage, according to a 2005 Oregon Health & Science University study. Snacking late at night can also exacerbate symptoms for those prone to heartburn, as lying down after eating makes it easier for stomach acid to flow into the esophagus.Break it Boredom, not hunger, is of the root cause of late-night eating, says Pamela Peeke, MD, author of Fit to Live. Once the craving hits, focus on an activity that engages you until it’s time to go to sleep, such as e-mail, a crossword puzzle, or meditation. It’s also common for people to chow down while watching TV. In fact, a study from the Smell and Taste Treatment and Research Foundation in Chicago found that people who were allowed to eat as many potato chips as they wanted ate 44% more chips while watching Letterman than while not watching TV. Keep your hands busy while you watch by folding laundry, using your BlackBerry, or knitting — that way you won’t be tempted to break out the Ruffles.
4. Bad habit: Smoking – We don’t need to remind you of all the health risks associated with smoking (heart attack, lung cancer, emphysema, and cancer of the mouth, throat, stomach, bladder, kidney, and cervix), but here’s one you might not have considered: money. Lots of it. The cost of one pack plus taxes averages $4.49, so if you smoke a pack a day, you’re turning a whopping $1,639 a year into nothing but smoke, ashes, and nice black spots on your formerly pretty pink lungs.Break it: Ask your doctor about drugs that can help kick-start your quitting process and help you combat cravings and withdrawal. For instance, Zyban, an antidepressant, helps reduce psychological withdrawal symptoms such as frustration, restlessness, anxiety, and irritability. Chantix blocks the effects of nicotine on your brain, which helps reduce cravings. According to a study, 44% of smokers were able to quit after 12 weeks using Chantix, and another study showed that Zyban was nearly twice as effective as a nicotine patch in helping smokers quit.
5. Bad habit: Sun Worshiping – Blame it on Coco Chanel — before she returned golden brown from a Mediterranean vacation in the 1920s, pale skin was in. But until the Morticia Addams look comes back in style, stick to self-tanning lotion: The sun’s UV rays damage your skin’s DNA, increasing your risk of skin cancer (not to mention sunspots, sagging skin, and wrinkles). In fact, as much as 90% of wrinkles, brown spots, and sagging are caused by sun damage, according to the American Skin Association.Break it: Wear sunscreen daily on the parts of your body that are exposed to the sun, even during winter. The skin cancer foundation recommends applying 1 ounce of SPF 15 sunscreen with UVA and UVB protection to your entire body 30 minutes before going outside on a typical day, and then reapply every 2 hours. If you’re spending the day outdoors, wear a wide-brimmed hat and cover exposed skin with clothing, preferably with built-in sunscreen.