Not to be simplistic but for BTs and geirim: this is why there should be ongoing mentoring. (Not that we all wouldn’t benefit.)
Good point about the yeshivos: there was a chinuch column in Yated a few weeks ago about a kid who wanted to wear his payos a certain way, and a good discussion about minhag, hanhagos (i.e. conduct not under the rubric of minhag), etc.