We’re not just talking about repetition of words, gender pronouns, dialogue tags (if it’s clear who’s speaking, dialogue tags should be deleted anyway), and names. We’re talking about two or more sentences that say the same thing in different ways. This usually happens because the author’s scared they won’t be understood and they’re trying to clarify their meaning. I once saw an entire paragraph that was pure repetition. The author was trying to clarify two things and it made a mess of the paragraph. We were able to streamline it into three, or perhaps it was four, sentences. Keep an eye open for things like this.
This issue also comes up with character description. One author kept beating the readers over the head with their character’s eye color. “Gray eyes”, “stormy gray eyes”, “slate gray eyes”. This character’s eye color was mentioned at least once in every scene they appeared in (which was a lot. They played a major role in the entire manuscript. Not a secondary character at all.), and sometimes it was mentioned more than once in the same scene. Another author wanted to make certain the readers knew their character possessed “flame-colored tresses”. Although that one probably qualifies as a pet phrase as well, because almost every time the character’s hair was mentioned, “flame-colored tresses” was thedescription. “She tossed her flame-colored tresses back.” “Her flame-colored tresses glinted in the sunlight.” “She ran her hand through her flame-colored tresses.” After the initial description of a character, mentioning eye color, hair color, etc., a few times over the entire course of the novel as a reminder would be fine. And I do mean a few times. Like maybe three times after the initial description, spread out over the entire manuscript. But that’s it. (See, I did my own little bit of repetition there, and even bolded it.)
Keep an eye on your descriptions. Telling us a few times that her eyes are emerald, or that his voice is gravelly is fine. Telling us at least once every time we see the character is not.