Marriage issues (getting married and/or husband/wife issues)
Well, for starters, it should be obvious that we no longer maintain the schedule for education/marriage as advocated in Avos.
And in that case, the mishna isn’t even dealing with relative terms (“al tarbeh…”) but absolutes (age 5, 10, 15, 18…).
I have to think that these changes are due to societal changes.
The Wolf