You join a meeting with another appointment immediately afterwards. As the discussion runs over, you stay because leaving feels abrupt. The next appointment loses time even though nobody in the room knew you had a limit.
Say at the beginning when you need to go. If your contribution concerns one agenda item, ask whether that item can come before your departure. Give the organiser enough notice to change the order if they want to.
Make the departure useful
Before leaving, summarise any decision or action that belongs to you. Ask where the remaining notes will be shared. You can then follow the relevant outcome without promising to attend the whole discussion.
When the meeting reaches your stated time, leave with a brief reminder. If an exceptional issue requires you to stay, make that choice consciously and address the effect on your next commitment. Afterwards, consider whether the meeting needs a different length or a clearer agenda next time.
