First, you need to understand that masturbation itself is not physically harmful & will not damage your reproductive system. It’s consideted normal behavior. If one is so addicted to masturbation that it’s affecting work or social plans, then that can become a problem, but otherwise, it should not be an issue. Of course, addiction to porn IS a serious matter, but unless that’s the case, there’s not a lot to be concerned about.
For men, it’s been shown that frequent ejaculation (21 times per month or more) may prevent development of prostate cancer later on, so unless you have a partner & are having frequent sex, you should be ejaculating 4-5 times/ wk, at least during your 20s & 30s & men who maintain frequent ejaculation in later years are also at lower risk. Bottom line - unless masturbation is interfering with other aspects of your life, there’s no physical or medical reason you need to stop.