While we agree that dine and dashing, aka “pulling a Noakhailla” is a no-no, overstaying your welcome isn't socially acceptable either. We've all encountered that one loud and obnoxious uncle who's had one too many, well, helpings of biryani and can be seen lounging well after the party has died. For the hosts, he's probably being a pain in the backside. It doesn't matter whether we do it unintentionally or unconsciously, but reading the situation in hand and understanding cues is key.
Most hosts will never spell it out for you to know when to leave. Keep these points in mind and you'll never have to worry about overstaying.
We all know how bad the traffic is, but if the invite is formal in nature, take necessary steps to reach the venue on time. Arriving 10 minutes late is acceptable but an hour is never a good idea. Oh and if you are late, that does not, in any way mean that you have to stay back late to make up for it. Don't be the first person to leave and never the last one.
Tone and body language
It's only normal for hosts to assure you that you can stay back, often to come off as hospitable. Sometimes they'd generally want you there. However, notice if there is any sign of reluctance in their tone or the number of times you've been asked to stay back. Gather information from their body language; see if the host has lost enthusiasm in whatever topic you're talking about. Or if your host doesn't repeatedly keep asking you to prolong your stay, know that it is time to exit stage.
Keep your auditory senses on guard. Look for keywords which your hosts might mention even though they don't want to be rude. Phrases like “it's been such a long day” or “I still need to prepare for tomorrow's meeting” usually means that the host is tired and not really in the mood to continue hosting, which is understandable since s/he had to prepare and entertain at the party. Thank them, and walk out that door.
There may be times when you are not invited to a gathering, but you want to drop-in and surprise someone. Steer clear of that idea unless you know that person well enough. However, if you are certain that the other person would be fine with the idea, make your visit as brief as possible. Unless the other person is genuinely surprised and wants you to hang around for a bit, don't linger around as that would make things very awkward.
Waiting for your carriage
If you have to wait around for your ride, politely ask the host if it is okay to sit around for that duration. Offer to help clean up after, since a dinner party would definitely leave a mess behind. The more humble you are, the more the chances are that your host doesn't mind having you there.