immediately after college, or even during college. The government encouraging wanton student debt is part of the problem. Parents spoiling their adult children by paying their tuition, buying them nice cars, and putting them up in luxury apartments during school are another part.
They all believe living within their means is something for a distant future and doesn't apply to them now. As if anything they learn in college, any professional credential they gain, could ever be more important for their lives and their family's happiness than that simple lesson.
When I was that age we had to walk to school uphill in the snow, paying our own tuition both ways.