I think masturbation is perfectly natural, to wank is a healthy thing most teenages (like me) do for pleasure.
I would say once every other day is normal
(I masturbate once a day)
I think it is normal, and that it will stop alot of the worlds issues such as STD Spreading, Unwanted Pregnancys(Solving many of the abortions) and alot of rape would seize. As for me when I was younger I would about 5 times a week now not so much.