Ready to retire? Congratulations. Now get to work.

Unless you're lucky enough to retire with a generous monthly pension, managing your retirement could become a full-time job. Skills required: investment know-how, risk management, the ability to project price increases and a keen understanding of the tax code.

Some retirees relish the challenge. Charles Abbott, 73, of Cincinnati, manages a portfolio of individual stocks, stock mutual funds and fixed-income investments. He subscribes to investment research firm Morningstar, reads "Value Line" at the library, and uses tools provided by Fidelity Investments, where he has his brokerage account. "I enjoy it," he says. "I'm on the computer a couple of hours a day."

Even if you don't share Abbott's enthusiasm for portfolio management, you may not have a choice. Only 21 percent of private-industry workers are covered by traditional pensions, according to the Bureau of Labor Statistics.

If you're not eligible for a pension, you'll probably have to rely on Social Security and personal savings, such as 401(k) plans and individual retirement accounts. You'll have to figure out how to make that money last 30 years or more. And unlike younger investors, you won't have a lot of time to recover from your mistakes.

Herb Paske, 66, of Riverwoods, Ill., is one of the lucky ones. A former school administrator who now works as a financial adviser, he retired from the school system with a pension. He also has an investment portfolio, but managing money is "a lot easier when you have a steady stream of retirement income," he says.

Many of his retired clients don't have that advantage.

For retirees who would rather go bowling than study price-earnings ratios, there are alternatives: