Hook

The convention in short form is that the hook lives in the first one to three seconds, because that is roughly where the largest drop in the retention graph appears. The number is a working rule rather than a platform rule: what actually matters is that the viewer learns what the clip is about and what they will get before deciding to leave.

It matters more than any other edit because everything downstream depends on it. A strong middle cannot be seen by people who left at second two, and the ranking systems judge the video largely on what that first audience did. This is why the same clip republished with a different first line can perform completely differently.

The nuance is that a hook is a promise, and unpaid promises cost more than a weak opening. Clickbait openings that never resolve lift the first seconds and destroy average view duration, which is worse than a plain start. Hooks also have to work muted, so the opening caption carries as much weight as the spoken line.

Practically, most creators write several hooks per idea and test them across posts rather than debating which one reads best. Clipping tools that propose multiple start points make this cheap, because the same footage can ship with different openings and the retention graph settles the argument within a day or two.