Repetition in dialogue or action in films and novels is tedious and redundant if it is experienced as repetitive.
In his book, Screenwriting, Richard Walters uses the film, Yentle, to illustrate this point. The film starts with a prologue informing us that in the Eastern Europe of the time, education was meant for men only. Moments later, a bookseller rides a cart through the streets advertising “scholarly books for men! Romantic novels for women!”
When Yentle gets to town she peruses the bookseller’s books, studying a scholarly tome in particular. Upon seeing this, the bookseller snatches the book from her and reminds her that such books are meant for men only. She should seek out romantic books instead.
This sort of repetition is condescending, implying that we are incapable of getting the point the first time around.
Repetition is acceptable, but only if it is not repetitive. This is not as contradictory as it sounds.
“Repetition of known information is acceptable only when used for emphasis.”
In Rashomon, four observers relate the same event. Here, however, each version differs in the detail, adding a unique and intriguing quality to the recounting. This is an exceptional use of a technique that examines the nature of human perception and truth.
In Unforgiven, we learn that the sheriff, Little Bill, is a tough antagonist to Clint Eastwood’s William Manny. To elevate the stature of the sheriff, the writer has a deputy emphasise his toughness by assuring the others that Little Bill is scared of no one, having survived a tough education in the mean streets of Kansas. This adds to Little Bill’s ruthless reputation, rather than being a mere repetition of information.
Repetition of information already provided to an audience or reader is condescending and unnecessary, except when it is specifically used for emphasis.