So you can imagine my movie-going was severely limited. And certainly did not include Taxi Driver.
But I couldn't help but think of this iconic scene when I was thinking about repetition in manuscripts:
He repeats several lines here, most famously: "You talking to me? You talking to me?"
There are times when repetition works in a scene. If DeNiro didn't repeat himself here (in a scene that apparently was more off the cuff than on a script page), it wouldn't have such a lasting impact in the film world and be so recognizable.
So writers are well within their rights to have repetition in a scene. Even in a few sentences close together. After all, that's sometimes how people talk.
But other times, it seems as if the writer had forgotten the character had already said that. That's especially true when it's information (Bob's my uncle; have you met Bob, my uncle?) as opposed to a reaction (Oh my God. I can't believe he left. Oh my God. He's gone?).
And there's times I catch exact wording a few paragraphs apart. Those instances make me wonder whether there was some self-editing going on and the repetition didn't get caught.
So if you've gotten a manuscript back from me (or any other editor) asking about repetition, we do recognize it can be an effective storytelling tool. But hey, it's our job to make sure you're telling your story, not getting stuck in Groundhog Day!