According to a study in the New England Journal of Medicine, smokers who kick the habit in their 40s or 50s can still reclaim many of the years that would otherwise be lost. The findings show that people who stop by the age of 40 reduce their risk of smoking-related death by 90 per cent, giving them a near-normal life expectancy. Those who stopped smoking at 45 to 54 years old gained about six years of life, compared with those who continued smoking, while those who quit at 55 to 64 gained about four years of life.