This is true. IMO, under 10% util is ideal.
Respectfully disagree. Having a zero balance when your card reports *does* hurt your credit score. I almost always pay off the balance on all of my cards each month without worrying about when the card companies report. When I've pulled my FICO reports during months when there's a $0 balance reported on all cards, FICO lists the fact that I have zero balances on my cards as a "NEGATIVE" factor, even though I've generated activity by using at least 3 out of 4 cards that month. This has happened 2 or 3 times in the past few years with Experian and TransUnion reports generated by FICO.