Image: Credit card © Hill Street Studios, Getty Images

The 30s are the debt decade.

Nine out of 10 people in their 30s are in debt, the highest proportion of any age decade, according to the Federal Reserve's most recent Survey of Consumer Finances.

Thirty-somethings also carry the biggest debt burdens. The median amount of debt carried by people in their 30s in 2007 was twice their median income: $110,600 of debt versus $54,503 of income.

These are also the years when the majority of people become homeowners (63.7%) and have children at home (71.7%), both potential budget busters.

Consider:

  • The percentage of households carrying credit card debt peaks in the 30s. More than half, or 53%, of households headed by 30-somethings fail to pay off their credit cards in full every month, and the median balance carried is $3,000.
  • Compared with other age groups, more people in their 30s have serious debt problems. Despite median income that's 76% higher than those in their 20s, people in their 30s are more likely to be 60 days late on a bill (9% compared with 7.9% in their 20s) and nearly twice as likely to be $10,000 or more in debt on credit cards (12.1% compared with 6.4%).
  • Fewer have student loans, but the balances are higher. One out of four 30-somethings still owes money for school, but the median balance is more than $15,000, compared with $13,000 for those in their 20s. This reflects the fact that the folks who didn't owe much were able to pay off their loans within a few years of graduation. Those stuck with payments in their 30s tend to be the ones who borrowed a lot.

Liz Weston

Liz Weston

The good news is that you're more likely to have access to a workplace retirement plan, such as a 401k, and to be using it to save.

Here are some of the things to keep in mind while charting your financial life in your 30s:

  • Corral your expenses. It's easy to let your living costs creep up on you, but if you want to get ahead financially, you may need to make some hard choices about your spending.
  • Pay off those credit cards. Carrying a credit card balance is bad for many reasons: You pay unnecessary interest on your purchases, and you're vulnerable to all kinds of credit card company schemes. And you cut yourself off from a source of funds in an emergency.

Speaking of which:

  • Build an emergency fund. A cushion of cash can protect you in case of job loss, illness, accident or other setback. Aim for an amount equal to one week's pay at first; try to build from there.
  • Watch your other debt. Make sure you can really afford the loans and other debt you take on. You'd be smart to limit mortgage debt payments to no more than 25% of your gross income and to be extremely cautious about auto debt.

    Click here to become a fan of MSN Money on Facebook

  • Continue to save for retirement. With all the other demands on your income, you may be tempted to suspend or reduce your retirement savings. Don't do it. Your contributions to retirement need to come first and to continue no matter what if you want to have a comfortable old age.

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.