Generally speaking, the length of a cigarette is 84 mm, and the golden section line is the best smoking position, that is to say, only about one-third of the places with cigarettes are smoked, and the remaining two-thirds should not be smoked. Theoretically, this is the best for health. Because the first third of the cigarettes are smoked, the remaining two thirds also play a filtering role. With the shortening of cigarettes, harmful substances will continue to increase and the taste of cigarettes will become worse and worse. Similarly, when the average smoking amount reaches one third, it just relieves the addiction and ensures health.