Sit Down for "The Lecture"

Did your parents give you "The Lecture"? No, not that lecture. I'm talking about the other lecture that was hard for them to deliver and uncomfortable for you to hear: The "you're on your own now financially, so don't blow it" lecture.

Whether you had a formal squirmy sit-down before your send-off into the real world or you had to learn your money lessons by going through the School of Hard Knocks, it's never too late to review the road rules for financial survival. Here's a crash course.

Don't get drunk with your purchasing power. Just because the bank says you deserve a $15,000 credit limit, that doesn't mean you can actually afford to spend that much. Just say no. Be a responsible user of credit. And remember: Credit cards are bad only when their owners misuse them.

Do the math. There's no bigger buzzkill than credit card debt. On a $2,000 balance subject to a 16% interest rate -- roughly the average rate on a student credit card -- it'll take you nearly seven years to pay it all off if you make only the minimum monthly payment. And that's even if you never charge another dime on the card. Oh, and don't forget to add about $862 to that tab, since that's what you'll pay in interest over the life of that balance. Do the math to see what you'll shell out for those late-night pizzas you can't afford, and you'll lose your appetite really quickly.

Be a model credit citizen -- your future depends on it. Establishing credit at a young age will give you countless financial-attractiveness points in the future. Display model credit card usage behavior now, and you're a shoo-in for the best rates on loans. You'll also enjoy high-fives from potential landlords and from future employers who check credit reports before asking you to sign on the dotted line. Behind door No. 2, however, is a less flattering future: High interest rates, coupled with denials in many walks of your financial life (see previous paragraph for reiteration).

Keep score. You do have a permanent record: It's your credit score, and it represents your financial GPA. Charge too much, make late payments, or apply for too many cards, and your credit score will suffer. FICO is the most widely used credit-scoring system, and payment punctuality and credit-use levels account for 65% of your FICO scoring equation. So pay those bills on time, and keep balances below 35% of your credit limit.

Don't buy that! Life is full of temptations to acquire more stuff. But seriously, do you really need that (insert whatever latest doodad that you thought you couldn't live without -- if you can even remember what it was)? Really? Again, do the math: Figure out how many hours you'll have to work to earn the money it costs to buy that outright. If you plan to pay for that with
plastic, calculate the real price -- the one that includes all of the interest. And remember, there are other options. Borrow that, buy that used (check coffee-shop bulletin boards and Craigslist.org), or pick that up for free (try Freecycle.org). Mother Earth and the credit-rating overlords will sing your praises.

Lastly, don't supersize your lifestyle. The key to achieving Zen-like financial balance is simple: Spend less money than you make. That's it! Lecture over.

Fool.com columnist Dayana Yochim insisted on being present when her parents gave her older brother "The Lecture" (yes, that one). She has blocked the episode entirely from her memory.