How long should a hook be for rap song?

There is no definitive answer to this, as the length of a hook for a rap song can vary depending on the song's overall composition and style. Generally speaking, however, a hook should typically be between 2 and 8 lines long, with 4 lines being the most common length. The hook should be catchy and memorable, as it is often repeated multiple times throughout the song. It should also be relevant to the song's theme and message, and help to create a cohesive listening experience.