Run-together paragraphs drive me nuts. Having to stop and figure out who’s saying what takes me right out of the story. With dialogue especially, each person needs his own paragraph. If one speaker says something, and the other reacts with a thought or motion but no words, then the second person should still have a new paragraph. It helps the reader keep the picture and the conversation straight.
“No, I don’t want to go there,” Lucy said, taking a book off the shelf. She kept her focus on the book. “It isn’t necessary.” John thought she seemed uneasy.
“We can talk about it another time.” John noted the book title: Sunrise in the Garden of Love and Evil. Was it significant?
Question: Who said “It isn’t necessary”? It isn’t clear whether it’s Lucy or John. You can assume from the paragraph breaks that John said “We can talk about it another time,” but if the writer has confused you before by not following this practice, you may wonder about that too.
All it needs is to break the paragraph when there’s a new subject or speaker, either before “It isn’t necessary,” if John said it, or before John thought . . . if Lucy said it.
Keep it clear!