Retirement savings for 40-, 50- and 60-year-olds

Your retirement lifestyle includes how you want to live in retirement and when you want to retire. "Some people are comfortable working longer than they originally planned to, if that will help them save more money and delay the time when they start spending their retirement funds," says Jennings. "Rethink your retirement objectives. You may be able to work part time in retirement."

You can also make adjustments to how you plan to live in retirement, says Corn. "It's about lifestyle, it's about how you want to live," he says. Maybe you had thought of buying a second home in retirement, and instead, because you haven't saved as much as you wanted to, you might have to downsize to one smaller home.

Deciding when to take Social Security is another factor, because you can get more monthly income if you wait until full retirement age, which for some people is as high as age 67. If you're married, you have two decisions to make. It might make sense for one spouse to take Social Security as early as possible and the other to wait, Corn says.