While we may not all be personal finance pros, we're all familiar with the money rules that kick in when we're adults: Don't charge over your credit
limit, never co-sign a loan for a friend, and don't forget to balance your checkbook.
That last one is about as natural a guideline to financial health as breathing oxygen is to living. But as we move further into the 21st century, people are writing fewer and fewer checks. While It's still possible to keep your cash and debit card purchases logged in a checkbook register, if you aren't carrying about a checkbook -- and if most of your purchases are made with your debit card or through ATM cash withdrawals -- it's a harder rule to follow.