I have never once carried a credit card balance or paid a cent in interest. My credit score is over 800 which is pretty much maxed out. The only things on my cr

I have never once carried a credit card balance or paid a cent in interest. My credit score is over 800 which is pretty much maxed out. The only things on my credit history are a few credit cards that I got to establish credit history, and my mortgage, which is why I needed a credit history. So I got 3 credit cards and used them each during each month so that I would established on-time payments on all three and boom, I had perfect credit after a couple years and qualified for a mortgage. I didn't use any credit before I decided to buy a house in my 30s so I had a completely empty credit history prior to that, apart from a library that reported a lost book. So it just took a little while to get my average account age up and my number of on-time payments above some threshold. Now if you don't use the card at all, it is less effective at establishing credit because you don't get the on-time payment history or balance. The credit bureaus just get reports of on-time or late payments, balances, and delinquencies/defaults, etc. You will be given the best rating at a small non-zero percentage of your total available credit being used each month, but it doesn't have to be carried. All you have to do is make sure you don't pay it off too early. Just wait until the due date, and pay off the statement balance, not the full balance. If you pay it off mid-month, before the end of the statement, or paid the full balance instead of what is due, you may get a zero balance reported which is a slight temporary hit to your score, but not that significant. I found that it was best to have a few cards with a total available credit at least 5 times my monthly spending. That way the reported balance ends up being <20% of my total available credit which is near the sweet spot. If I am going to do a refi on my house i might try to micromanage it to somewhere close to 5% for a few months ahead of time and get a few points added to my score, but once you get your score up around 800 it doesn't really matter if it is up or down 10pts or so. I found that as my average account age increased, the swings from slight differences in balance were smaller.