The questions should be explicit, things like when and how long for and where in the house will an extra person sleep. Then there is the issue of payment: whether there is any, to start, and then if so how much and if not money for board then perhaps for food or power or Netflix, or will the houseguest be expected to help instead with other matters – the cleaning of rooms, the caring of children, the contributing to family life in some other, less tangible way.