To clarify -- I was referring to paying cards off each month. I swap them around so none is inactive. I also push about as much through them as I can manage without going to Herculean efforts to do so. Cash back is a nice benefit. 🙂 You do have to have the discipline to not go buy stuff you don't have the cash to pay off immediately.
The card providers will report the balance as of each statement, so the credit report will show a utilization. As I didn't clearly communicate, paying off each balance before it's due results in plenty of benefits with no downside while still showing some utilization. (FWIW I just did a refinance on my home and so I'm freshly familiar with my credit report and score) 🙂
Point being -- if you're actively using cards, you'll show some utilization due to how the card providers report, even if you're paying balances to zero every month. Just wait until you get the statement then zero it out.