I have a substantial amount of credit available to me. All of my credit cards either have either a 0 balance or are under 30% usage(1 out of 6). Yet, 3 months ago, I decided to use a credit card I hadn't used in a while for a minor purchase, with the intention of keeping the card active and my credit score dropped 40 points on all 3 credit bureaus. I can't understand why. Any idea what's going on here?
