I and, coincidentally and separately a long-time friend, were homeless for a year while undergraduates. It was a financial necessity to stay in school full time (while working part-time) and not take out student loans. That was over 40 years ago. We both went on get Ph.D.s and become part of the middle class. As homeless students we were a rarity, but it wasn't unheard of--a former roommate student camped out of his car for half a year--just couldn't give up that car.