People give all kinds of reasons for why they started smoking, but none of them are good not even supposedly altruistic ones.
While some claim that you're actually saving our overburdened healthcare system money in the long run by smoking because it reduces life expectancy, it's nowhere near a watertight argument.
First of all, you're certainly not doing your family and friends a favor by deliberately lowering your life expectancy. In fact, your family will have to absorb the losses incurred when you miss work due to smoking-related illnesses. Second, there is a lot of debate over the best way to measure the economic costs of smoking.
Every study is based on different assumptions, and uses different data and methods. For example, should you measure the cost of smoking by looking at the cost of treating major illnesses like lung cancer and heart disease, or should you also measure the cost of less serious illnesses? Should you take into account the fact that people who live longer also pay more taxes and insurance premiums? Should you look at the overall cost to the healthcare system, or at the cost per individual?
Anyway, regardless of how you calculate them, the economic costs of smoking are inconsequential when compared to smoking's real price: the misery caused by the deaths of over 400,000 people each year and the illnesses of several million.
- The economics of tobacco: myths and reality (NIH)
- Economic Facts about U.S. Tobacco Production and Use (CDC)