Research shows that most smokers get motivated to quit very suddenly, spurred into action by a specific event, milestone or resolution.
Smokers who use their local stop smoking service are up to four times more likely to successfully stop smoking for good.
Find your local stop smoking service or ask your doctor, pharmacist or health professional to refer you.
Don't go it alone, there are many reasons to stop and lots of help is available for free.
Use one of these key times to get, and stay, motivated to quit.
Why quit? Around 7 million of us will make a New Year's resolution to improve an aspect of our health, and stopping smoking is one of the most common ones.
Break down your goal into smaller steps and reward yourself when you achieve one of these. Tell your friends that you are stopping smoking, focus on the benefits – financial and physical – of success and keep a diary of your progress.
Stay motivated: There's lots of free quitting support available to help you achieve your goal – find out more at NHS Smokefree.
Read more about how to stick to New Year's resolutions.
Why quit? If you are thinking about having a baby, or you're already pregnant, you have two big reasons to stop smoking. Both you and your baby will be healthier, and you will be less likely to have problems during the birth.
Every cigarette harms you and your baby. If you smoke during your pregnancy you increase the risks of miscarriage , and your baby is more likely to be born prematurely and with birth defects.
Being exposed to secondhand smoke is also harmful to your unborn baby. So, if your partner smokes, ask them to quit or at least stop smoking around you.
Stay motivated: If you're lucky, you'll be one of the women who can't stand the smell of smoke because of morning sickness , and that will make it easier to cut out cigarettes.
You'll probably find that your daily routine will change throughout pregnancy, too. Take advantage of the change to break the link with nicotine.
The NHS Smoking Helpline on 0300 123 1044 offers free help, support and advice on stopping smoking when you're pregnant, including details of local stop smoking services. You can also sign up to receive ongoing advice and support at a time that suits you.
Read more about quitting smoking in pregnancy.
Why quit? Every year, around 1 million smokers, especially women, use No Smoking Day to try to quit. The British Heart Foundation charity estimates that more than 1.5 million smokers have quit for good since the day's launch in 1983 – that's more than 45,000 every year.
So if you choose to stop on No Smoking Day, you'll know you're not alone, you really are one of 1 million people. Think about how good you will feel knowing that you tried, you succeeded and you got what you wanted.
Stay motivated: The British Heart Foundation's has tips for quitters.
Why quit? Maybe you've decided to start an exercise programme or take up a new sport, and you've noticed how smoking-related symptoms, like shortness of breath, affect you when you exercise.
Smoking can dramatically reduce your endurance, meaning that you will take longer to recover after exercise. But as soon as you quit, you'll find that you feel fitter, less breathless and better able to play sports.
Stay motivated: Not only will you become fitter when you stop smoking but exercise will also help you to maintain your focus.
There's evidence that exercise will improve your mood and dampen cravings in the early stages of quitting. It will also help to stop you putting on weight when you quit.
Boost your fitness with fun and practical ideas to help you get into shape, from exercising at home to learning to dance.
Why quit? You probably want to spend as much time with your new grandchild as possible and, if you smoke, you could be harming the baby's health. Consider how your son or daughter may feel about you smoking around their baby.
Moving to the other side of the room to smoke, going into another room to smoke or opening a window doesn't completely remove the risk. It can take two and a half hours or more to clear a room of secondhand smoke. Even if you can't see or smell any smoke, it can still be there.
Stay motivated: Remember that you're doing this for your own health and that of your grandchild.
Read about the risks of passive smoking and how the NHS can help you to stop smoking.
Why quit? If you have a long-term or life-threatening condition, it's a good time to quit smoking. A major illness is a life-changing event that could help you break your addiction.
You may think the damage is already done or that it's too late to quit – but that's not true. Your health can start to improve within 20 minutes of smoking that last cigarette.
Stay motivated: As part of the treatment for your condition, your doctor may recommend that you change your lifestyle by reducing stress, eating more healthily and doing more exercise. Knowing that this will help your recovery will keep you going.
Why quit? Because hospitals are in the business of making people well, many of them don't allow smoking on their grounds at all.
Seeing a stay in hospital as an opportunity to stop smoking for good is a far more positive step than going there feeling angry that you won't be able to smoke.
If you're having an operation, there's the added incentive that, if you stop smoking before you go into hospital, you'll recover more quickly and there will be less chance of complications.
Stay motivated: Ideally, you should stop smoking about eight weeks before you go into hospital.
If you want help preparing, ask your doctor or a member of the hospital staff for help with stopping smoking.
Read more about going into hospital .
Read more about 7 steps you can take straight away to stop smoking.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.