Why do cigars need humidors in the first place. How do they even work? For starters, a humidor is a container that stores your cigars. It can be in the form of a small box as a travel humidor or it can be as huge as a walk-in humidor as used by cigar shops. No matter the size, a humidor will have a good seal to maintain the internal temperature with the help of a thermostat and hygrometer.