The rationale: Because you can pay your bill with a few computer clicks, you figure you have plenty of time.

The rebuttal: Failure to factor in enough time for account processing (and mailing, if you take the snail mail route) when paying your credit card bill can be disastrous, Ray says. Credit reports indicate late payments in 30-day increments, so any payment overdue by 30 days or fewer counts as 30 days late. The penalty for that mark against you can be a late fee, a bumped up interest rate and a lower credit score. In fact, your payment history accounts for about 35 percent of your credit score.

When most of the CARD Act provisions go into effect Feb. 22, card issuers won't be able to raise the rate on an existing balance unless the consumer is 60 days behind with the payment. They could jack up your rate if you were 30 days late, but the higher rate would only apply to new transactions.

Paying online is more foolproof than snail mail. You get confirmation of your payment when you submit it and at the same time the credit card company tells you how long it will take to process it.