If you’re a smoker, chances are you’ve already tried to quit. So you know from experience that it’s not easy. Many ex-smokers say quitting was one of the hardest things they’ve ever done. But many do succeed in the end. And the health benefits they gain make quitting worth the effort.

There’s no question about the harm smoking can do. Tobacco is the leading cause of preventable death nationwide. If you smoke, you’re up to 6 times more likely to suffer a heart attack than non-smokers, and the risk increases with the number of cigarettes smoked. Tobacco is also one of the strongest cancer-causing agents. Up to 90% of lung cancer deaths are attributed to smoking.

The good news is, as soon as you stop smoking, your lungs, heart and blood vessels start getting better. When you quit, you greatly reduce your risk of cancer, heart disease, stroke and early death. Within a year of quitting, you’ll have cut your risk of developing heart disease by nearly half. You’ll feel more energetic and breathe more easily. And you’ll be protecting the health of the people around you. Quitting can even save you money. If you smoke a pack a day, quitting could save you up to $150 a month.

Although you know that quitting is a smart thing to do, chances are you’ll still find it tough. “If you have trouble quitting, or if you’ve had trouble in the past, you’re in the majority,” says Dr. Glen D. Morgan, a scientist at NIH’s National Cancer Institute (NCI). “We know that the more attempts that people make to quit, and the more they try, the greater their chances of success in the long run. People can capitalize on their previous efforts to quit, and they can learn from them.”

Why is it so hard to stop smoking? After months and years of lighting up, smoking may be part of your daily routine. “Maybe you’ve developed certain patterns of smoking, like having a cigarette after a cup of coffee or when you’re talking on the phone,” says Morgan. “Or maybe you smoke when you’re stressed, or when you get into the car or put on your makeup.” You may light up without even thinking about it.

You might even feel uncomfortable not smoking at times or in places where you usually have a cigarette. These times and places are called “triggers” because they trigger, or turn on, cigarette cravings. For many smokers, breaking these habits is the hardest part of quitting.

Your biology can also play a role. You may be addicted to nicotine, a chemical found in all tobacco products. Nicotine can make you feel calm and satisfied, or alert and focused.

The more you smoke, though, the more nicotine you’ll need to feel good. If you become dependent on nicotine, you may not feel normal without it. And when you try to quit smoking, you may feel dull, tense and not yourself while your body gets used to life without nicotine. Called “nicotine withdrawal,” this feeling usually lasts for only a few weeks, but it leads many to return to their cigarettes to feel normal again.

Several research teams have also found that genes can affect how hard or easy it is for you to quit. Last year, Dr. Caryn Lerman of the University of Pennsylvania School of Medicine and her colleagues reported that they’d found variations in genes that seem to influence whether a smoker has a better chance of quitting using nicotine replacement therapies or a drug called bupropion, or Zyban. “But these studies are still in their early stages,” says Lerman. “More research is needed before we can translate the findings into a genetic test that can help smokers quit by personalizing therapy to their individual needs.”

Some find that a combination of medication and support from friends or counselors helps them to quit, but others have had success without medication. “We know that there are many effective ways to quit smoking. There’s no single ‘right’ way,” says Morgan. “The key is that you need to be motivated, and you need to be prepared. You need to develop a plan, and put the plan into motion.”

The first step, many experts suggest, is to set a quit date. Think about choosing a special day—maybe your birthday or wedding anniversary or World No Tobacco Day on May 31.

Next, tell others about your plan. It’s easier to stop smoking if you have support from your friends, family and co-workers. Last year, an NIH-funded study found that changes in smoking behavior can spread through a social group. In many cases, spouses, friends, siblings and co-workers decided to start smoking or quit for good around the same time. Try asking your spouse or friends to quit with you, or at least not to smoke around you.

You should also be ready to face difficult moments. Most people who go back to smoking do it within the first 3 months. Plan for how to deal with the smoking urge before it hits. Throw away all your cigarettes and matches. And get rid of all the things that remind you of smoking in your home, in your car and at work.

For additional help, you can get over-the-counter medicines—like the nicotine patch, nicotine gum or nicotine lozenge—from your grocery store or pharmacy. For other medicines, you’ll need a prescription. Talk to your doctor or pharmacist about medications that have been approved by the U.S. Food and Drug Administration (FDA) to help you quit.

For example, Lerman says, “The newest drug on the market is called varenicline, or Chantix. It reduces levels of nicotine withdrawal and craving.”

NIH offers several free resources to help you quit smoking. If you live in the United States, you can call NCI’s toll-free Smoking Quitline (1-877-44U-QUIT, or 1-877-448-7848) and talk with a counselor in English or Spanish. Or get confidential advice and information from NCI’s online chat service at https://cissecure.nci.nih.gov/livehelp/welcome.asp. You can also visit Smokefree.gov, an easy-to-use web site with lots of information and tips to help you quit.

It takes time to break the smoking habit. Don’t give up too soon. You may need more than one try to quit for good. But others have succeeded, and so can you.