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.

Some people dont know when to end calls early and everyone else is too polite to tell them to end it. I had a manager who made it a point to suggest to end a call early. I try not to force calls to end early unless I know everyone on the call. I notice when its all devs its really easy to suggest ending early vs when non devs are on a call unless a dev manager does it.