I'm keep receiving the messages such as:
We notice you aren't using your X Card. Call X for a PIN, ... Or X for a new card.
So the question is, how Credit Card inactivity impacts my credit scores? Does that hurt/lower it?
If you have zero activity on a card, the issuing bank may decide to close that card. They have some costs each month, and if you aren't using the card they aren't making money off of you.
Your inactivity is also a risk because if you lost the card, and don't realize it, and it falls into the wrong hands then it can be used for fraudulent transactions. In their view it might already have been hijacked.
If they close your account that can hurt your score: your utilization number will go up, and the age of your accounts could go down.
They want you to use their card so they make money on the transaction fees and hopefully interest payments.
According to Clark Howard you should use your cards every 6 months to keep them in your active credit score mix.