If you're not going to set a time or if you're not going to follow the time that you have set for a meeting, don't be offended when I leave partway through a conversation. I think the philosophy that a meeting should not be longer than one hour should be followed. But a meeting that lasts more than three hours, with no break, is taking the piss. You wonder where your productivity goes Japan? Get rid of meetings, or at least set a time limit.