When you're enjoying yourself at your friend's dinner party, it can be incredibly easy to lose track of time while partaking another glass of wine or after-dessert coffee.
But according to etiquette expert, Thomas Blaikie, to be polite and please your host, you should always leave the gathering at a particular time.
On a weeknight you should leave by 10:30pm, while on the weekend you should aim to leave by 11:15pm.
Mr Blaikie revealed these preferred dinner party curfews in his column in The Lady magazine, as a response to a reader's question.
He wrote in the column, called Modern Manners, that it is best to leave naturally, turn down an offer for an after-dinner drink and avoid hard spirits, as this can prolong your stay.
"Left to their own devices, guests can reach a point beyond which they've lost the will and the energy to leave, having previously perhaps been wishing to leave but feeling it was too early and all their energy went into that agony, so there is none left when the time to leave has long passed," the manners connoisseur wrote.
"Especially if the hosts, rather hoping that the guests will leave, offer them more and more, such as a hard drink like brandy, diminishing almost to vanishing point any hope of departure."
After-dinner drinks, whether alcoholic beverages or a cup of tea of coffee, can be too much for the dinner party host, so it is polite to turn them down.
If you want some more advice on how to fine-tune your manners, you can have a read of Mr Blaikie's book Blaikie's Guide to Modern Manners (£3.06, Amazon).
This sounds like good advice, but we also think that it massively depends on how well you know your hosts. If they are good friends, we should trust our judgement that they would be more offended if we did turn down a whiskey!