(MONEY Magazine) – Most people's foremost fear in planning their retirement is simply outliving their money. Yet that terror can be tamed by Social Security, a pension and a well-planned program of personal savings and investments.

What should rank as the No. 1 financial fear of growing old is the cost of long-term care for people too feeble or crippled by illness to look after themselves -- a nonstop expense that can quickly deplete resources built up over a lifetime.

Now this problem too can be alleviated. Growing numbers of insurance companies are offering long-term-care policies that are more comprehensive and affordable than earlier versions. The longer we live, the more likely it is that we will have to pay others to dress and groom us, feed us and move us around.

Americans' life expectancy at age 65 is increasing dramatically. Since 1940, the chances of living another 20 years have doubled, from one in five to two in five, and they are expected to rise to three in five by the year 2030.

With longevity comes a new set of medical problems. Where once debility came largely from strokes, cancer or other acute diseases, for the over-85 generation it is more likely to come as a gradual loss of the ability to take care of oneself. People live for years with chronic ailments such as Alzheimer's disease and osteoporosis, which seldom require long hospital stays but render the victims more and more helpless.

In the past, the duty of caring for them fell to their children or other family members. Now, with the generations dispersed geographically, the givers of care tend to be paid strangers.

The cost can be crushing. At average rates, nursing homes charge $73,000 a year, and the fees are escalating in step with inflation. Home-care services, which include physical therapy, administration of drugs and food preparation, are $80 to $150 a day. Few people are up to the costs.

Last summer a congressional subcommittee on aging found that 70% to 80% of nursing-home residents used up all of their capital in a year or so and were forced onto welfare.

Once impoverished, nursing-home patients usually have to move to less desirable accommodations in the same facility or to a less costly institution. Most Americans have done little or nothing to prepare for the high risk of needing long-term care -- or its catastrophic cost. One reason is that they assume Medicare will pick up their nursing-home bills. But it's not true.

Medicare pays only for stays in skilled nursing homes -- ones staffed with doctors and nurses -- and then only if admission follows a hospital stay. Further, this coverage is limited to 100 days per admission.

Supplemental Medigap plans, which you can buy from private insurers, pick up part of the medical expenses that Medicare doesn't pay. But Medigap too excludes long-term care. So does the catastrophic coverage that Congress is likely to add to Medicare this year. The new plan is aimed at expenses resulting from acute illnesses such as heart attacks and injuries such as bone fractures.

Long-term care necessitated by the gradual enfeeblement of aging rather than acute illness is uncovered except by Medicaid (Medi-Cal), the medical welfare program for & the indigent. Worse yet, many of the most desirable nursing homes discourage -- or refuse outright -- applicants who are on Medicaid (Medi-Cal).

The best choice for most people is to buy their own long-term-care insurance policy. The premium is likely to be more than $5,000 a year if you put off the purchase until you are past 65 and you are less likely to be insurable at that age because of health problems.

Whether you should sign up for long-term-care insurance depends largely on your age. Since purchase of long-term-care policies is limited to those in good health and few companies sell insurance to anyone over 80, it is prudent to insure yourself by age 50 or so.

How many days of care come out of your pocket before your benefits begin and how long they continue will greatly influence the premium you pay. Most insurers offer at least two choices of waiting periods, typically 20 to 100 days. Selecting a 100-day waiting period can reduce your premium. So choose as long a waiting period as you can afford.

An average policy would provide benefits for three years. Extra coverage, however, can mean the difference between solvency and bankruptcy for those whose confinement continues for years.

Some people require medical services; others just need personal care. Some people can get along in their own home; others have to be in a nursing home. Ideally, a long-term-care policy should offer the widest possible options, including nursing homes in three categories of medical care: skilled homes; intermediate homes, which provide rehabilitative therapy; and custodial homes, which offer little more than practical nursing. The best policies also pay for care at home, adult day-care centers and brief intermittent care at a nursing home, also known as respite care.

Alzheimer's disease can leave victims helpless for 15 years or longer. That's why some insurers exclude ''organic brain disease'' from the conditions their policies cover and why you shouldn't buy any such policy.

Renewability. Be sure your coverage will continue for as long as you want it to and that your premiums can't be hiked unless everybody's are in your area. In the language of insurance, such a policy is guaranteed renewable.