Within the first pages of a screenplay a reader can judge the relative skill of the writer simply by noting how he handles exposition. - Robert McKee

As he chooses, he is.

Anxious, inexperienced writers obey rules.
Rebellious, unschooled writers break rules. Artists master the form.

Pace begins in the screenplay. Cliche or not, we must control rhythm and tempo. It needn't be a symmetrical swelling of activity and shaving of scene lengths, but progressions must be shaped. For if we don't, the film editor will. And if to trim our sloppy work he cuts some of our favorite moments, we have no one to blame but ourselves. We're screenwriters, not refugees from the novel. Cinema is a unique art form. The screenwriter must master the aesthetics of motion pictures and create a screenplay that prepares the way for the artists who follow.