In the USSR, you usually don't have a spare guest room. An unmarried young man would be lucky to live in a separate apartment; otherwise, it is usually just a bed in a dormitory. At best, it is a one-room (12-20 m2) apartment with a kitchen (10 m2). A hotel is too expensive, so you put your guests into your bed, a folding chair, or a folding cot and go to the kitchen to sleep on a mattress. There were families of 4-5 people who lived in such apartments permanently.