It is not possible to generalize. With the individual's libido strength and physical fitness, there is a certain relationship. Usually, around thirty years old, sex once every 2-3 days is normal; around forty years old, sex once every 4-5 days is normal; around fifty years old, sex once every seven to eight days is normal. The frequency of intercourse in youth can often determine the frequency of sex in middle and old age. Sexual desire is strongest between the ages of 18-25 for men and 35-45 for women