It is discussed several times on forum that masturbation is a bad habit but it is allowed in cases where the person has no other options to discharge. No doubt that masturbation has no harmful effects on health BUT Excess of everything is dangerous. example: food is our basic requirement, it gives us plenty of benefits but what happens if a person eats 10times/day? water is essential for life, but what is the condition of person if he drinks 5litres water per day?
sex is the basic functional capability of humans like the other basic bodily function i.e. eating, sleeping, walking, talking etc. it should be taken as a routine function of body.
Penis is like a machine, the more it is used, the more it functions.