Her best piece of financial advice, "Pay off your credit card debts asap, cut them up. If you must keep one, pay it off in full when the bill arrives."
I think the best advice is keep 2-6 accounts at 30% or less of the credit limit. If you pay off an account, keep it open and use it once a year of whatever the comapny requires to keep a credit history.
It's my understanding if you don't have a couple of accounts, it can lower your credit score. Anything a person can do to keep their FICO high will give them financial options throughout their lives and enable them to save when they have to borrow.