... but at one time your habit of never running balances would flag you as a "deadbeat".
Not no more. More significant is whether you miss payments (especially more than one) or don't make the minimum payment or similar misdemeanors which would make you a credit risk. Often, "decluttering" one's credit card accounts substantially lowers one's credit rating; it's better to let a credit card company close your account (say, for non-use) than to do it yourself.
Credit card companies actively troll for credit card users who use credit cards extensively and who settle their accounts promptly. They make their profit off the merchants' 3%-4% fees.
Good credit ratings now seem to be used more widely. For example, my insurance providers offered a major discount for a good credit rating (which required my permission), since those with good credit ratings have been found to make fewer insurance claims — which is precisely what insurers look for.
