Question

How is the need for line memorization in theater actors similar to or different from the need for line memorization in film actors?

Answer 1

It is more critical for theater actors to have their lines firmly memorized because their performances are going to be live.  With a TV or film actor, for the most part, they can ask for the line and retake the shot.  There are a few live television shows but for the most part, things are recorded so while it is important for film actors, it is imperative for theater actors.