Nicotine is a very addictive drug. People usually try to quit many times before they are successful. In September 1990, the US Surgeon General outlined the benefits of quitting smoking:
Quitting smoking has major and immediate health benefits for people with and without smoking-related disease. Former smokers live longer than continuing smokers. For example, people who quit smoking before age 50 have one-half the risk of dying in the next 15 years compared with people who keep smoking. Quitting smoking decreases the risk of lung cancer, other cancers, heart attack, stroke, and chronic lung diseases such as emphysema and chronic bronchitis. Women who stop smoking before pregnancy or during the first 3 to 4 months of pregnancy reduce their risk of having a low birth-weight baby to that of women who never smoked. The health benefits of quitting smoking are far greater than any risks from the small weight gain (usually less than 10 pounds) or any emotional or psychological problems that may follow quitting. Your risk of having lung cancer and other smoking-related cancers is affected by how much you have been exposed to cigarette smoke over your lifetime. This is measured by the number of cigarettes you smoked each day, how old you were when you started smoking, and the number of years you have smoked. There is no way to accurately calculate a person's risk of getting cancer, but the more you smoke and the longer you do it, the greater your risk.
The good news is that the risk of having lung cancer and other smoking-related illnesses can be reduced if you stop smoking. The risk of lung cancer is less in people who quit smoking than in people who continue to smoke the same number of cigarettes every day, and the risk decreases as the number of years since quitting increases.
People who stop smoking when they are young get the greatest health benefits from quitting. Those who quit in their 30s may avoid most of the risk due to tobacco use. However, even smokers who quit after age 50 largely reduce their risk of dying early. The argument that it is too late to quit smoking because the damage is already done is not true. It is never too late to quit smoking!