According to the World Health Organization, there are immediate and long-term health benefits of quitting for all smokers. Beneficial health changes that take place:
– Within 20 minutes, your heart rate and blood pressure drop.
– 12 hours, the carbon monoxide level in your blood drops to normal.
– 2-12 weeks, your circulation improves and your lung function increases.
– 1-9 months, coughing and shortness of breath decrease.
– 1 year, your risk of coronary heart disease is about half that of a smoker’s.
– 5 years, your stroke risk is reduced to that of a nonsmoker 5 to 15 years after quitting.
– 10 years, your risk of lung cancer falls to about half that of a smoker and your risk of cancer of the mouth, throat, esophagus, bladder, cervix, and pancreas decreases.
– 15 years, the risk of coronary heart disease is that of a nonsmoker’s.
If you want to know more about the benefits, read this post from the W.H.O: http://www.who.int/tobacco/quitting/benefits/en/