Taking a cash advance
The rationale: An emergency comes up or a big bill comes due, but you don't have enough in your bank account to cover it so you get a cash advance.
The rebuttal: Tapping into cash available through your credit card to get out of a financial jam will cost you dearly. You'll probably incur an interest rate that's several points higher than your normal rate for purchases. On top of that, there's a transaction fee that's typically either 2 percent to 4 percent of the advance, a flat fee, or some combination of the two. There's also no grace period for cash advances, so you get hit with interest charges immediately.
Consider asking your creditor for an extension, getting a loan from a family member or even putting the bill payment on your credit card (but pay it off in full when you get your statement). Use the card to get cash only as a last resort.
"I think cash advances are a reasonable thing in an emergency," Birkofer says. "But a cash advance to pay your rent tells me that you're not managing your cash right. There's something out of whack with either your income or expenses."