I think if masturbation becomes a hindrance to living a life one intends to...then it may be a problem. I do what I do with masturbation and other form's of sexual relief that adds to my life's sexual sanctification.

As I wrote with regards to hindering ones wishes to live a good sex life or a good life in general. Having a behavior that keeps one isolated, fearful, shamed or problematic in other aspects of a health life. Then maybe its time to look for making changes. Other than that...enjoy yourself... masturbation is very healthy.