This is gonna be explicit. If we want a society that doesn't watch porn, then men's sexual partners need to be willing to get them off around once/day. Handy or BJ at least. If a woman doesn't do that for her man, then he's gonna masturbate, and that's when porn will inevitably come in. Maybe future studies in sperm health could shed some data on this topic and provide a more optimal rate than once/day, but once/day seems like a good approximation for now. At sperm donation centers, you need to have ejaculated at least once previously in the last three days before donating; they don't want sperm more than three days old. There are men's movements throughout history (running the gamut from ancient Tantric & Daoist, to modern Proud Boys) who claim that it's healthier for a man's sexual system to abstain for months at a time; frankly, I don't think there's any science behind that, but I could be wrong. I trust the sperm donation center science.

If a woman gets her man off at least once/day, then he really doesn't have an excuse for watching porn. And he should be able to last trips of a few weeks without watching porn as well, resisting the urge to watch porn while masturbating. Of course, the man's duty in this is to be clean, and to be thankful to his woman.

Overall, https://www.hubermanlab.com/ has stated that assessing the health of a man's sperm is a useful proxy for assuming how healthy the rest of the man is. The healthier the sperm, the healthier the rest of him probably is. This is an important topic on the level of health, and frankly the best wisdom we have is from sperm donation centers: sperm more than 3 days old is too old. - Now, what to advise teenage boys. I dunno. You're not gonna convince a teenage boy either to not masturbate for years, or to masturbate but not watch porn for years.