alt Hacker NewsGoing to add the most important thing: It is perfectly fine to end calls early if it feels like it has phased itself out. Don't be afraid to do so! Everyone on the call is costing someone else a lot of income. This goes for internal or external calls.
Yes, seriously. When a sales call is scheduled 30 minutes but 5 minutes in we have a conclusion, you get a lot of good will points from me if you thank me for my time, ask me if there's any other questions I have, and then conclude the call. You can even make this explicit with a quip like, "I'll give everybody 20 minutes back!" then it's clear you are being courteous with our time.