Should you edit your own movie? This is a question I think needs to be asked more often. Some of the great directors never edit their own films and others do. Kevin Smith and Robert Rodriguez famously edit their own material, as does James Cameron, but he usually is on a team of editors with him. Steven Spielberg never edits his own films and relies on Michael Kahn as he has for 35 years with only 2 exceptions in his feature film career. Why would you want to work with an editor?
I cite as an example a single scene from Star Wars A New Hope from 1977. The scene where Luke and the droids are sitting with Ben Kenobi in his house. In the script and in the shoot, the scene started with R2D2 showing off the hologram of Princess Leia saying “Help Me Obi Wan Kenobi” and then they talk about the Clone Wars. Do you remember this scene?
During post production, editor Paul Hirsch looked at this and told George “I don’t think this is right. You have the princess begging for help and saying her ship was under attack, and THEN you have Ben and Luke talking casually about his father and going on about historical things. I think we need to reverse this because once you see this hologram, they need to be in a hurry and get on with the story…” and George agreed. As a writer/director, sometimes you are so close to the material you lose sight of how the audience will view it. Simple mistakes like this might slip past the goalie if you are creating in a vacuum.
Paul Hirsch won an Oscar ™ for Star Wars by the way…
Editing is the process of possibly fixing mistakes and re-motivating characters. It’s a 3rd chance, after the script (1st) and the shoot (2nd). They call editing the Final Re-Write for a reason.