Providing readers with information they need to know is necessary, of course, and a great way to do that is by using dialogue. You have to make sure, however, to avoid what I call “soap-opera dialogue.” You shouldn’t have characters discussing things they already know just for the benefit of the reader. Chitchat like this is called soap-opera dialogue because it’s used in soaps frequently to help viewers who may have missed a few shows. Example:
Rick: “Jeff got here about ten minutes ago.”
Todd: “Jeff? That sleazy attorney who broke up with Natalie last week after Dr. Lebowitz told him she had a brain tumor?”
Rick: “Yep. He flew in this morning. I guess he figures that big murder trial of his in New Orleans can go on without him.”
In conversations like this you can almost see the characters winking at each other. Never use soap-opera dialogue in your novel.