5. Understand investing basics

Manny Schiffres, executive editor of Kiplinger's Personal Finance, says: Before you invest in anything, do a little homework to understand what you're getting into. Sometime in the mid-'70s, when I was in my mid-20s, I made my first investment -- a tax-free bond fund. I was so obsessed with cutting my tax bill, despite having a lowish tax rate, that I put my money into an investment that offered little potential for growth.

And because we were in a period of rising interest rates, I wound up losing a penny or two per share every day, and I had no idea why. Plus, I'd missed out on making good money by investing in stocks, which performed pretty well for the rest of that decade once the 1973-74 bear market ended.

6. Beware the dangers of credit cards

Mark Solheim, senior editor of Kiplinger's Personal Finance, says: Don't get a credit card until you are certain you have the money and discipline to pay off the entire balance every month.

When I graduated from college and wanted to take a summer publishing course, I didn't have enough savings to pay all my expenses. My dad gave me a "loan" in the form of one of his credit cards with the stipulation that I would pay off the balance on my own. My salary from my full-time publishing job was just enough to cover food, rent and gas, with nothing left over for debt payments. It took two years and a slew of extra odd jobs -- painting, mowing lawns -- to finally retire my debt.

7. Don't buy what you don't need

As for me, I wish I'd thought twice about buying a car after I graduated from college. As someone who grew up in small-town Ohio and attended college in Indiana, it didn't occur to me that in the big city of Washington, D.C., I could get by -- and save a ton of cash -- without my own set of wheels.

I took $239 a month out of my entry-level salary to make loan payments on the barely used Honda Civic I had purchased. Plus, I had the usual expenses for gas, insurance, property taxes, registration, repairs and maintenance. All of that for a car that was nice to have around but that I didn't really need. I thought about selling it, but Mother Nature eventually made the decision for me: Several tree branches fell on it as Hurricane Irene whipped past D.C. last summer, totaling the car. The insurance payback now serves as a nice cash cushion for emergencies, and I use car-sharing service Zipcar when public transportation won't do.

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