Which factor is critical for an actor to perform well according to rehearsal practices?

Memorization of lines is a fundamental aspect of an actor's preparation that allows them to deliver their performance with clarity and confidence. By having their lines thoroughly memorized, actors can fully engage with their scene partners and the emotional content of the piece, rather than being distracted by the need to remember what comes next. This clarity enables them to respond more naturally to the flow of the dialogue and interact authentically on stage.

In addition, memorized lines free up cognitive resources that can be redirected towards other performance aspects, such as physicality, emotional depth, and character development. When an actor is confident in their lines, they can focus more intently on their character's motivations and relationships with others in the scene, leading to a more compelling and cohesive performance. Ultimately, memorization allows actors to create a more cohesive piece of theater where all elements work harmoniously together.