I had a scene in my book, The Smart Kid, where I named a student who had no role in the story at all. His only purpose was to bring up a historical topic about the Equal Education bill for Handicapped students of 1975.
One of the critiques from the monthly writing group was “Don’t name someone who is unimportant.”
I think that is a good rule.
If you put a name on a character, then that implies that they are important, or that perhaps the character will appear again later in the novel. Readers don’t know what is important as they read through a scene or chapter. It is up to the author to give clues as to what to pay attention to.
Along that same topic is how an author draws attention to an event. In an early draft of my novel I spent a number of paragraphs describing how one teacher called the principal who called the counselor who called the main character for a meeting. And, since there were about 3 other characters involved in the process, it added extra weight or importance to the event, which turned out to be a rather minor meeting.
So the reader was expecting something really important because it such a large build-up. Lots of sentences on a topic draws attention to it, and says to the reader, “Pay attention to this. It’s important!”
So spending a number of paragraphs on a topic, is just like naming a character. It adds meaning and importance and it should be for a reason.