I was a grad student at Harvard in the math department too. In my time there was a student who decided he was going to sleep in his office (I don't think sleeping outside is such a great option in the New England winter). These offices are small - there's a desk, then room for a chair, and shelves for books above the desk. They are essentially for solo work. Anyway, this student was handling it fine - showering in the university gym and doing laundry in the basement of the nearby graduate residence halls, and rolling his bed up in the morning so as not to be reported by the cleaning staff. Then his girlfriend visited from abroad and she was so appalled with the suggestion that they bed down together essentially under his desk, that he ended up having to pay for them to stay for a week in a decent hotel. After that he found himself an apartment-share pretty quick.