The example of a big room to allow for friends to sleep over is rather bad. Just keep few thick mattress toppers that one can put to the floor in case of overni

The example of a big room to allow for friends to sleep over is rather bad. Just keep few thick mattress toppers that one can put to the floor in case of overnight visit. If someone needs more comfort, just stack 2 of them. Compared with normal mattresses they can be rolled and do not take much space. Plus it is faster to prepare a bed on the floor with them than even with guest sleeping sofa.