You asked about priorities to stress to your teenage son as he begins to think about marriage one day. I know these are not exhaustive, but it should help you form an outline. I would stress three things:
First, I would stress “savings.” Eating out with friends is a luxury, not a habit. As for clothes, I would encourage him to have a couple of nice suits for special occasions. Look for quality, but don’t allow them to be drawn by the idiotic commercialism of the day. Also, if he doesn’t have a bank account, he needs to open one up now. If a man comes to me one day and says, “I would like to date/court your daughter,” but has nothing in his savings account, I would like to kindly encourage him to come back later when that scenario has changed. How much savings should he have? Enough to show his competence. Situations will vary, but that’s a good starting place.
Second, I would stress “skills.” If your son’s skills are limited to a box in his room, you need to have a conversation. Let’s assume he has no idea what he wants to do. There are aptitude/career tests he can take. And I would certainly encourage him to talk to a pastor or teacher who may know a bit more about his abilities. If he does have something specific in mind he wishes to pursue, like engineering or business, he still needs to have an additional skill to fall back in the interim. There are always gifted people in your local church from whom he may learn or even do an internship.
Finally, I would stress “service.” If your son is not engaged in helping the local church or if he is merely a consumer at home, that needs to change. If he is to love his future wife, sacrifice for her, serve her in sickness and in health, and yet, has no interest in serving right now, that is problematic. A service-oriented husband is not created in one day.
Much more could be said, but I hope this helps you direct your son in the right direction.