One lesson we've taught both our kids is that you always need a minimum of six months of living expenses easily accessible so you're prepared for an emergency and more importantly, do not have to pass up business opportunities because you can't afford to temporarily lose your income.
Money management is NOT taught in the schools, unless you go to college and major in a financial field. Most of us learned it from a mentor. I guess I was an exception to that rule, as I squirreled away some time to teach my students a bit about investing in their own future. While the subject matter I was teaching was science, quite a number of my former students who contacted me thanked me for what I did in that regard. I always told them that they had to be smart enough to absorb and use the lessons.