at close quarters

In or occupying a cramped or rather small space with other people; the term "quarters" is a reference to military housing. I'm glad to be done with my student days. Living at close quarters with so many people just to afford rent is something I don't want to do again.

Crowded, in a confined space, as in We could use a lot more room; this tiny office puts us at close quarters. This idiom makes figurative use of quarters in the sense of "military lodgings" but originated in 18th-century naval warfare. When the enemy boarded a ship, the crew would retreat behind wooden barriers erected for this purpose and would continue to fire through loopholes. They thus were very near the enemy, fighting in close quarters. [c. 1800]