During the second world war my mother outstayed her welcome in a neighbour's house one evening.
The matter was resolved when one of the sons of the house, a young man in his late teens like my mother, announced:
"You're sitting on the chair I put my clothes on when I go to bed."
Fuel was in such short supply in Copenhagen then, that families only heated their living-room, undressed there and left their clothes on a chair before racing into their freezing bedrooms.
As a catch phrase the saying survived in my childhood home for years.
I myself, if people do not take the hint and it is getting late, state frankly that it is past my bedtime and that I will be pleased to see them again soon.
During the day, I would say something like, "I've enjoyed this chat, but it is playing havoc with my to-do list for today, so can we continue it later this week, please?"
If people cannot take a hint, I see no harm in being frank.