In my horror novel, Hello Darkness, Hank is a mild-mannered, God-fearing hardware store owner in the small town of Falling Rock. Hank is not one of the book’s main characters and is only mentioned a few times (and seen once) before his moment in the spotlight.
So why does he get even a little bit of the story? The reason is because there’s a lot going on in Falling Rock—evil is nesting in the woods just outside town, and most of the main characters are still unaware of its existence. However, the reader needs that little peek behind the curtain so they aren’t asking the same question for a hundred pages. Asking questions is good (essential, even) but a question that evolves over the course of a novel is even better.
Enter Hank Buckley.
He stumbles into a little bit of bad luck that provides a great opportunity to widen the view about what’s going on in the book. Through Hank’s eyes I am able to give the reader one more piece of the puzzle that everyone else in the story is still trying to figure out. It’s not exactly a spoiler, but it’s enough of a reveal to let the reader know there is something huge going on—something deadly. Hopefully, it creates a little bit of suspense throughout the rest of the book. The reader knows what lies in wait for the good people of Falling Rock even if the characters don’t.
I don’t think there should be any hard and fast rules when it comes to Point-Of-View (POV) in a story. As long as you aren’t head-hopping and ripping people out of the moment, do whatever you need to further the narrative. That’s why the characters exist in the first place—to help tell your story. Use ’em. Toss ’em. Make new ones. Whatever enhances the reader’s experience should be a writer’s first priority.