When smokers quit -- What are the benefits over time?

20 minutes after quitting:
Your heart rate and blood pressure drops.
(Effect of Smoking on Arterial Stiffness and Pulse Pressure Amplification, Mahmud, A, Feely, J. 2003. Hypertension:41:183.)

12 hours after quitting:

The carbon monoxide level in your blood drops to normal.
(US Surgeon General's Report, 1988, p. 202)

2 weeks to 3 months after quitting:

Your circulation improves and your lung function increases.
(US Surgeon General's Report, 1990, pp.193, 194,196, 285, 323)

1 to 9 months after quitting:

Coughing and shortness of breath decrease; cilia (tiny hair-like structures that move mucus out of the lungs) regain normal function in the lungs, increasing the ability to handle mucus, clean the lungs, and reduce the risk of infection.
(US Surgeon General's Report, 1990, pp. 285-287, 304)

1 year after quitting:

The excess risk of coronary heart disease is half that of a smoker's.
(US Surgeon General's Report, 1990, p. vi)

5 years after quitting:

Your stroke risk is reduced to that of a non-smoker 5 to 15 years after quitting.
(US Surgeon General's Report, 1990, p. vi)

10 years after quitting:

The lung cancer death rate is about half that of a continuing smoker's. The risk of cancer of the mouth, throat, esophagus, bladder, cervix, and pancreas decrease, too.
(US Surgeon General's Report, 1990, pp. vi, 131, 148, 152, 155, 164,166)

15 years after quitting:

The risk of coronary heart disease is the same as a non-smoker's.
(US Surgeon General's Report, 1990, p. vi)

Immediate rewards of quitting
Kicking the tobacco habit offers some benefits that you'll notice right away and some that will develop over time. These rewards can improve your day-to-day life a great deal.
your breath smells better
stained teeth get whiter
bad smelling clothes and hair go away
your yellow fingers and fingernails disappear
food tastes better
your sense of smell returns to normal
everyday activities no longer leave you out of breath (such as climbing stairs or light housework)

Cost
The prospect of better health is a major reason for quitting, but there are other reasons, too.
Smoking is expensive. It isn't hard to figure out how much you spend on smoking: multiply how much money you spend on tobacco every day by 365 (days per year). The amount may surprise you. Now multiply that by the number of years you have been using tobacco and that amount will probably shock you.
Multiply the cost per year by 10 (for the next 10 years) and ask yourself what you would rather do with that much money.
And this doesn't include other possible costs, such as higher costs for health and life insurance, and likely health care costs due to tobacco-related problems.

Social acceptance
Smoking is less socially acceptable now than it was in the past.
Almost all workplaces now have some type of smoking rules. Some employers even prefer to hire non-smokers. Studies show smoking employees cost businesses more because they are out sick more. Employees who are ill more often than others can raise an employer's need for expensive short-term replacement workers. They can increase insurance costs both for other employees and for the employer, who often pays part of the workers’ insurance premiums. Smokers in a building also can increase the maintenance costs of keeping odors down, since residue from cigarette smoke clings to carpets, drapes, and other fabrics.
Landlords may choose not to rent to smokers since maintenance costs and insurance rates may rise when smokers live in buildings.
Friends may ask you not to smoke in their homes or cars. Public buildings, concerts, and even sporting events are largely smoke-free. And more and more communities are restricting smoking in all public places, including restaurants and bars. Like it or not, finding a place to smoke can be a hassle.
Smokers may also find their prospects for dating or romantic involvement, including marriage, are largely limited to other smokers, who make up less than 20% of the adult population.

Health of others
Smoking not only harms your health but it hurts the health of those around you. Exposure to secondhand smoke (also called environmental tobacco smoke or passive smoking) includes exhaled smoke as well as smoke from burning cigarettes.
Studies have shown that secondhand smoke causes thousands of deaths each year from lung cancer and heart disease in healthy non-smokers.
If a mother smokes, there is a higher risk of her baby developing asthma in childhood, especially if she smoked while she was pregnant. Smoking is also linked to sudden infant death syndrome (SIDS) and low-birth weight infants. Babies and children raised in a household where there is smoking have more ear infections, colds, bronchitis, and other lung and breathing problems than children from non-smoking families. Secondhand smoke can also cause eye irritation, headaches, nausea, and dizziness.

Setting an example
If you have children, you probably want to set a good example for them. When asked, nearly all smokers say they don't want their children to smoke, but children whose parents smoke are more likely to start smoking themselves. You can become a good role model for them by quitting now.

* http://www.cancer.org/