Not a minute longer than it needs to be

"I would have written a shorter letter, but I did not have the time." That's the problem. Making something shorter takes effort. You'd need to review the whole recording, decide what to cut, and make sure the meaning survives. Nobody has time for that, so the video ships at whatever length it happens to be.

ExplainItOnce handles it automatically. How much shorter depends on what you recorded:

Training videos typically get 10 to 20% shorter. Presentations get 20 to 30% shorter. General updates and walkthroughs can be up to 40% shorter.

A shorter video tells the viewer: this is what you need to know, and nothing in here is wasting your time. That makes it more engaging and more likely to be watched to the end.