There are three legs on the retirement stool: Social Security, pensions and personal savings. According to an Employee Benefit Research Institute (EBRI) study, one of those legs, Social Security, is a bit wobbly, providing on average only 40 percent of the income needs of persons 65 and over.

For pre-retirees, this is a wake-up call. Since Social Security doesn't supply enough income for people to get by financially for even two weeks of each month, how do you make up the difference? According to the EBRI study, pensions and annuities account for about 20 percent of income for the over-65 population, though this percentage may decline as companies terminate pension plans and taxpayers object to generous benefits for public sector employees.

The upshot is that people over 65 will need to rely on earnings and personal savings to meet nearly half of their retirement income needs. It's a scary thought, but one that needs to be confronted.

Develop a game plan

Start by figuring out where you stand right now. Use AARP's Retirement Nest Egg Calculator to crunch the numbers on your current savings and your future income needs. If you come up short — as many people do — think about ways to close the gap, perhaps by increasing your savings and prudently investing those funds that are earmarked for retirement.

Some retirement savings vehicles are better than others. Workplace plans like 401(k)s and 403(b)s offer immediate tax savings, tax deferral later on, and perhaps an employer match. If you have income from self-employment, even part time, self-employed retirement plans offer excellent tax advantages as well. If you can also afford an IRA, make annual contributions. Roth IRAs hold particular appeal for many.

It’s not too late to get started

If you're rapidly approaching retirement age, or find yourself forced to retire early due to job loss or health problems, here are some last-minute strategies to close the gap:

• Downsize. If you can get by with a smaller residence, downsizing (or renting) can free up needed funds and reduce your living expenses.
  
  
• Relocate. Moving to a lower-cost locale in the U.S. or overseas after retirement can also cut your cost of living.
  
  
• Put off retirement. You can increase your savings, perhaps dramatically, by continuing to work, if you're able to do so.
  
  
• Delay Social Security. Delaying Social Security benefits can result in a higher benefit check for the rest of your life.