Match Blocks to Viewer Intent
I plan length backward from where the video will live and what the viewer should do after watching. A testimonial we produced for a healthcare software client in Boca Raton was edited to about three minutes because it had one job: let a happy customer explain the product. A YouTube explainer can run longer if each section answers something the viewer came looking for.
Before recording, I outline the sections and give each one a rough time. If a section cannot justify its time, it gets cut on paper, which is much cheaper than cutting it in the edit.
For scripted pieces, read the script out loud at a natural pace and time it, especially if the talent will use a teleprompter. For interviews, I plan more questions than we need, because the useful answer often comes on the follow-up. In that case the outline sets a target, and the edit decides the final length.