NEW YORK (CNN/Money) - Think about your retirement savings. For many of us, that nest egg is our single largest asset -- and now that nest egg is under assault.

After two-and-a-half years of market losses, and roughly 30-percent declines in the past four months alone, Americans are changing their assumptions about retirement. Portfolios have been decimated and 401(k) balances have shriveled. According to a recent survey in Time Magazine, two respondents in three, or 66 percent, said they plan to work full- or part-time jobs after they end their current jobs or careers. (see more from Time)

How serious all this is depends largely on how close you are to retirement.

For that reason, MONEY's retirement guide this year offers three age-based plans. Select from the groups below to start getting your retirement plan in order.

The losses seem devastating now. But you also have enough time to bounce back, especially since what you've saved so far is only a fraction of what you will save. READ MORE

If you're in your 50s or early 60s, preparing for retirement can be a schizophrenic pursuit. You need to invest aggressively enough to make up for losses or lack of planning, yet conservatively enough to preserve the wealth you've created so far. READ MORE.

There's no worse time than a bear market to start drawing down your nest egg. As a retiree, you have one overriding concern: making sure your money lasts as long as you do. In an era of reduced return expectations and rock-bottom interest rates, you face the daunting task of figuring out how to use your portfolio without using it up. READ MORE