What retirement calculators don't tell you

-- They're selling something. Some calculators look complex enough while you're putting in data, but then the results say things like "consider buying an annuity. And long-term care insurance. And a better health policy." Some companies are better than others, but any calculator that is sponsored by any seller of financial products has, as its ultimate intent, the selling of more financial products. Never buy anything just because an online calculator says you should. Even some that appear to be independent are sponsored by industry-funded groups, and may make your situation seem more dire than it really is.

-- They assume you can't, or won't, make adjustments. It's not a good idea to plan your retirement down to the last nickel without leaving room for error, or the occasional anniversary cruise. But most retirees handle their family budgets just as they did when they were working: If they aren't making ends meet, they cut back on spending or earn more. An early-retirement part-time job, or a shift from dinner and a show to potlucks and rented videos can make a huge long-term difference in a family's retirement lifestyle.