A mortgage is one of the few exceptions, and even then you should carefully consider whether renting or buying makes more sense. A car, notably, is not a good exception.

Education depends heavily on return on investment; you'd want to carefully analyze how much more you'll make with that education, how long it'll take you to pay off the debt, etc. It can certainly make sense when attempting to bootstrap yourself if your alternative is no higher education at all, but if you're in a financial position where you have to borrow for tuition, you may well qualify for better options such as scholarships. If you're reasonably well off and borrowing to go to a higher-end school, that makes much less sense.

And yes, the savings -> years to retirement table came from a Mr. Money Mustache article: http://www.mrmoneymustache.com/2012/01/13/the-shockingly-sim... .