Another thing we do in the editing process is notice the phrases and words that crop up repeatedly.
Unlike what is happening when we notice images that recur in the work — how those images can signal structural invitations for the book or deepen your understanding of the subject matter and how to communicate it — this kind of noticing invites you to pause and sharpen your skill.
This part of the editing process is about finding the just-right words and phrases, about making the language sing with the cadence of your book's voice, about removing any hindrances or obstacles or distractions to your reader's experience.
Repetitive words and phrases can be that distraction. They can make your reader keenly aware of you as writer, rather than you as narrator, such that they begin to critique the way you wrote it instead of being absorbed by the stories and ideas.
In those places of recurrence, pause and ask yourself: Is there a more fitting word or phrase I could use here? Is there some way I can help the language feel more fresh?