Rooting out repetition is one of the primary tasks of a copyeditor. Repetition can get annoying for the reader, and repetition can create wordiness. This is why rooting out repetition is such an important job for the copyeditor.
Ugh. Let’s try that again.
Enemy
Echoes
Writers sometimes unintentionally repeat words and phrases, creating distracting echoes. Many times these are common, useful words that come easily to mind when you’re trying to get ideas down on the page—linguistic low-hanging fruit as it were.
In fiction these overused words are often body parts: eyes, faces, hands—and things body parts do: look, glance, feel, smile, sigh.
Other times an item important to the plot or a noun that's the subject of a paragraph creates the echoes. If you’re describing a neighborhood, the word house is likely to crop up numerous times. And if you’re writing an essay about milk processing, it’s pretty tough to avoid repeating the word “milk.”
And then there are writer tics, those pet words or phrases that writers particularly enjoy or rely on. I worked with a writer whose characters frequently “waved a dismissive hand," a useful action beat for conveying a character's attitude, but when it popped up again and again, it drew attention to the act of writing—and away from the story.
How much is too much?
It depends. With the exception of nouns central to the story, unusual or distinctive words (or words used in a unique and clever way) probably shouldn’t appear more than a few times in an entire book. Sometimes even two occurrences is one too many. A character “galumphing” in one scene may be brilliant, but characters galumphing throughout your novel? Comic. One well-used “jejune” and readers may be appreciative; a second, and they may wonder if you have a word-of-the-day desk calendar.
A common word, on the other hand, is capable of flying under the radar until it reaches a bothersome level of frequency and/or density. It would take a lot of ands, buts, hes, or shes (or several close together) before they started feeling repetitive.
Fresh ears
Your own writing can become so familiar that you can't hear the echoes. Putting your manuscript away for a few weeks before revising or self-editing can help with this, as can reading your work out loud. Your beta readers and critique partners are a valuable resource: instead of just asking for general feedback, request that they keep a lookout for writer's tics and repeated words.
Collateral Damage
So we've established that repetition can hurt your writing. But, while blasting away at the enemy, careful not to shoot yourself in the foot!
Fancy words
Attempting to avoid echoes can lead to other issues. Simply changing the repeated word to a synonym sometimes works, most often with modifiers or verbs, but this technique can seriously backfire with nouns. Bill O’Sullivan, in a post on Jack Limpert’s blog, said this:
Watch out for word repetition … on the other hand, beware writers who strain to find an “original” word: tome instead of book, spectacles instead of glasses, pooch or Fido instead of dog.
My eleven-year-old daughter, who likes(?) to listen to me blather about editing and blog post ideas, offered this example:
Yeah, Mom, you wouldn't want to avoid repeating "milk" by substituting "moo-juice" or "liquid produced by mammals."
No arguments here!
Vague words
Sometimes the only synonyms available for concrete nouns are less specific nouns. Avoiding repetition by substituting the word "structure" for "house," "building," or "shack" may be an attempt to strengthen your writing, but it ends up weakening it instead. In It was the Best of Sentences, it Was the Worst of Sentences, June Casagrande has a chapter titled "Words Gone Mild: Choosing specific words over vague ones" where she writes:
Words like "structure" and "items" and "person" usually have no business in your sentences. They're just wispy shadows of the things they're trying to represent.
The fix? If the repetition isn't bothersome, restore the concrete word, and if it is, restructure the surrounding sentences to avoid having to repeat the problematic word. One thing to try is combining sentences, which may allow the formerly repeated noun to function as the subject for both verbs, or to be replaced by a pronoun.
The dog bit the man. And then the dog started foaming at the mouth.
An awkward attempt to avoid repeating "dog":
The dog bit the man. And then the canine started foaming at the mouth. X
Combining to fix:
The dog bit the man—and then started foaming at the mouth. ✓
Misleading words
Some synonym substitutions can create confusion for the reader.
Suppose you're reading an action scene, and the hero "gets into his SUV and races away, the bad guys in hot pursuit in their red Camaro." During the ensuing chase, the hero's SUV gets mentioned a few times, and then suddenly you read, "The truck was sideswiped by a speeding van." What truck? How many different vehicles are on this road anyway?
Sometimes SUVs are referred to by the word "truck," it's true, and this hypothetical writer was probably just trying to avoid repeating SUV too many times in the scene. But better to repeat yourself than force your reader to come to a screeching stop during a car chase.
Friend
I was recently reading Artful Sentences by Virginia Tufte, and I was struck by how many of the example sentences used repetition to marvelous effect:
And not long after that, I was reading Paper Towns by John Green and came across this chapter opening:
So it's important not to get so robotically task-focused—"must eliminate repetition!" that you overlook artistry. Sometimes an author's attempt might not quite achieve the desired effect, but if you can recognize the attempt, you can, instead of editing out the repetition, help the author use it more effectively, and perhaps push it even further.
To quote Bill O'Sullivan again:
Careful copyeditors listen to sentences as much as they read them.