According to the Gemara, one may not burn incense in order to perfume his home or clothing, because lighting a fire on Yom Tov is permitted only for something that most people enjoy (shaveh le-khol nefesh). Perfuming homes and clothing is done only by overindulged people. However, spices may be placed on coals to improve the flavor of the food being cooked on them. Even if the food would be tasty without the spice, anything that improves the food’s flavor is permissible. Since poor people would spice their food too if they had spices, it is considered shaveh le-khol nefesh. However, most people are not interested in perfuming their homes and clothes, as they consider it excessively self-indulgent (Beitza 22b; SA 511:4; see 3:6 above and n. 4).
Initially, some poskim were inclined to forbid smoking tobacco on Yom Tov because it entails Mav’ir. They maintained that since smoking was not so widespread, it could not be considered shaveh le-khol nefesh and was thus prohibited (MA 514:4; Korban Netanel, Beitza ch. 2, 22:10). Others disagreed, maintaining that smoking was indeed shaveh le-khol nefesh (Darkhei No’am, OḤ §9). In the course of time, smoking became more widespread. There was even a time when doctors thought that it was healthy and aided digestion. Therefore, most poskim were inclined to permit smoking cigarettes on Yom Tov (Pnei Yehoshu’a; R. Yonatan Eibeshutz; Pri Megadim, Mishbetzot Zahav 511:2; Ketav Sofer, OḤ §66; BHL 511:4).
In recent times it has become clear that smoking is extremely unhealthy, and that halakha forbids smoking altogether. Those who are already addicted must do their utmost to break the addiction. In fact, the percentage of smokers is decreasing and now stands at under 25% in Israel and under 20% in the United States. Since according to many poskim, the permissibility of smoking on Yom Tov was based on the reality that most men smoked, nowadays, when most do not smoke, some say that it is forbidden to smoke on Yom Tov, as it can no longer be classified as shaveh le-khol nefesh. Others permit smoking for those who suffer if they do not smoke. Since the motivation of smokers is not self-indulgence but the avoidance of suffering, and since everyone does whatever he can in order to avoid suffering, smoking can be considered shaveh le-khol nefesh. Additionally, it may be that shaveh le-khol nefesh need not require a majority of people, but only a significant percentage. Even though it is clear that smoking is harmful and smokers must try to quit, as long as they have not succeeded in doing so, they are not required to suffer specifically on Yom Tov (Tzitz Eliezer 17:21; Hilkhot Ha-mo’adim ch. 16 n. 1). In practice, le-khatḥila, smokers must try not to smoke on Yom Tov. One who finds this excruciating may rely on those who are lenient.
Since a fire may not be extinguished unless it is for okhel nefesh, smokers must be careful not to put out their cigarettes after they burn down. Rather, they should leave them somewhere safe, where they will burn out on their own. While smoking, people must also be careful not to knock off the ash at the end of the cigarette, because it is possible that this will extinguish ember contained in the ash. Rather, they must allow the ash to fall off by itself.