Quit smoking—the earlier, the better
Smokers live over ten years less on average than nonsmokers. Quitting before 40 removes roughly 90% of the excess mortality associated with continuing. The earlier you quit, the more years you regain.
What it takes
Quitting saves money: a pack a day costs about RMB 20–30 in China. The hard part is withdrawal, usually lasting weeks to months.
What you may gain
A US observational cohort found current smokers had life expectancy more than 10 years shorter than never-smokers. Quitting before 40 eliminated about 90% of the excess mortality from continued smoking. Quitting at ages 25–34, 35–44 and 45–54 gained about 10, 9 and 6 years respectively, as reported in the original. Chinese cohorts found that in the 2010s male smokers' mortality was 1.65 times that of nonsmokers in cities (RR 1.65) and 1.22 times in rural areas. After 10 years of voluntary cessation, the excess risk was nearly gone.
Context & considerations
Other people's smoke also kills: about 603,000 deaths worldwide in 2004, roughly 1% of all deaths that year, were attributed to secondhand smoke. Avoid it even if you do not smoke, especially around children. Practical help follows: medicines, a quit date, cessation services and e-cigarettes.
Research & references
Jha P et al. (2013). 21st-century hazards of smoking and benefits of cessation in the United States. NEJM. https://doi.org/10.1056/NEJMsa1211128 ; Chen Z et al. (2015). Contrasting male and female trends in tobacco-attributed mortality in China: evidence from successive nationwide prospective cohort studies. Lancet. https://doi.org/10.1016/S0140-6736(15)00340-2 ; Oberg M et al. (2011). Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries. Lancet. https://doi.org/10.1016/S0140-6736(10)61388-8 (the secondhand-smoke figures).