Do teenagers and people who have yet to begin working professionally have the self awareness for this good advice?
The problem is we are entering into relationships before we truly discover ourselves.
I do not speak out of superiority — I picked while in college and made the same mistake myself. So long as we pick partners in High School or College prior to commencement of meaningful careers, while some will blossom, many others will not and as such will make a mess of the marital choice.
The bigger problem perhaps is post divorce people refuse to acknowledge their contribution to breakups of relationships formed before they discovered themselves as such are no healthier for new relationships than they were in High School or College.