Upload defaults

It lives in Studio under Settings, Upload defaults, split across basic info and advanced. Anything set there arrives already filled in on the next video, so you edit from a starting point instead of a blank form.

Set visibility to private and nothing can ever go public by accident while you are still working on it, which is the single line most worth changing. A standard description block with your links, plus a base set of tags, saves a few minutes every week. It only touches new uploads. Existing videos keep whatever they already had.