<prompt> Human: I mostly keep my balance to zero, am I doing that wrong?  <response>: This is actually based on modeling going back years. Historically those with a 0 utilization rate have a lower credit scores than those with some utilization until you get to 30 utilization or higher. Here is a link to an article on it, Utilization versus average credit scores and while it predates current models this still stands true.In my opinion, the thought is by not using your credit you have not proved you can use it effectively. They prefer a long term proof that you can handle debt correctly and make payments on a regular basis. 