1. Script Supervisor
Film shoots are hectic, chaotic and non-linear. It is sometimes easy to forget an important detail in the rush of things. Something that will bite you later on in the editing suite. What would happen if it was a key line hadn't been recorded because it was forgotten (it happens) or there is a conflict of emotions from one scene to another because they were shot months apart in the schedule or it was simply a continuity issue. These are all things that happen frequently on a film set but if there is a good script supervisor, these things can be avoided. In charge of the 'internal continuity' of the film, the script supervisor is very intimate with the script. Most of the time they will know it better than a director and an actor and will always know where a shoot is within the terms of the script and where it has come from. There is often a period of liaison with the director as they express their desires and intention for each scene. The script supervisor will be aware of this all throug out shooting and will have detailed knowledge of what the director wants and the footage that has been shot. On top of that, they are sometimes worried with just the simple old continuity. When you are picking up a shot 6 months after you shot a scene and you need to remember whether a hand gun was in the left or right hand or the hair of an actor is parted to the left or the right at the drop of the hat, that is where a good script supervisor will show their worth. If you are ever lucky enough to direct a feature film, get a great script supervisor. It will save you a lot of heartache in the edit suite.