Editor's Note: Associate Editor Karen DeMasters writes the Social Security beat. Please send ideas to her at [email protected].

Deciding when to start taking Social Security benefits is more complicated than just deciding what is right for the primary beneficiary. If the beneficiary is married, he or she needs to take into account what the decision means for the spouse.

A common mistake is not looking ahead at how long the spouse may live after the beneficiary dies. The spouse can be dependent on those benefits for many years, says Brian Parker, managing director and co-founder of EP Wealth Advisors in Torrance and West Los Angeles, Calif.

"A lot of people just look at their own life expectancy and base their decision on when to start collecting Social Security on that, when they should also be looking at how long their spouse might live after they die," he says.

Most people try to determine at what age they would break even if they wait to collect monthly benefits until their full retirement age, usually 66 years old, rather than starting early at 62, when they get less per month.

"Generally speaking, the breakeven point is about 15 years between taking lower benefits early at 62 and higher benefits at the later full retirement age of 66. A lot of people think they would rather have the money in their 60s and 70s than their 80s," says Parker, a majority of whose clients are retired. "But I believe many retirees make this decision based on their personal situation rather than taking their spouse's future into consideration, so taking early benefits may not be the best decision."

If a couple lives to be 65, there is a 72 percent chance one of them will live to be 85, a 45 percent chance one will live to be 90 and an 18 percent chance one will live to be 95. Chances are it is going to be the woman who lives the longest and she may be totally dependent on the survivor benefits she receives from her late husband's earning record, especially if she has no earnings record of her own to draw on or if her earnings were lower than her late husband's.

Whatever amount the husband receives when he starts collecting is the amount that will be collected for the rest of his, and then the survivor's, lifetime, plus cost-of-living increases, according to the Social Security Administration.

If the husband wants the wife to collect as much as possible after he is gone, he will wait until at least full retirement age, and if possible he will wait until age 70 to begin collecting because the benefit grows each year until then.

"Maybe Social Security should be looked at as old age insurance as we continue to live longer, as opposed to trying to maximize income early in retirement," Parker says. "Many people want the money early because they have had to make sacrifices during their working years, such as foregoing travel."

The survivor can start collecting survivor benefits at age 60, but the amount will be reduced for each month the survivor collects before reaching full retirement age, which is gradually being raised to 67. Also benefits end if the survivor remarries before the age of 60, unless that marriage ends in divorce. To collect survivor benefits, a marriage must have lasted nine months unless a minor child is involved, then the child is entitled to benefits.

If the survivor has her own earning record but the survivor benefit is more, she can collect the survivor benefit while letting her own benefit grow until the maximum of age 70. If and when her benefit exceeds the survivor benefit, she can switch and start collecting under her own higher benefit amount.

The same limits apply to a survivor collecting benefits but continuing to work that apply to a primary beneficiary who collects while working. Generally, $1 is deducted from the benefit for every $2 dollars earned over a certain limit until the person reaches full retirement age. The limit for 2012 is $14,640.

A divorced spouse also can collect survivor benefits if the marriage lasted 10 years. The same age limits and limits for working while collecting apply. The surviving former spouse has the option of collecting the survivor benefits, while letting her own benefits grow until she reaches age 70 and then switching if her benefits are higher, the Social Security Administration says.

A major difference exists for the deceased's earnings credits when calculating survivor benefits. Normally, a person needs 40 earnings credits, which takes about 10 years to accumulate, in order to be eligible for Social Security benefits. However, the children and the surviving spouse who is caring for the children can receive benefits if the deceased accumulated six credits during the three years before his or her death.

Disabled surviving spouses can collect starting at age 50 but the benefits will be reduced by 28.5% from what they would be if she had waited until full retirement age.

The surviving spouse can collect 50% of the deceased's benefits if he or she is caring for children under the age of 16 and the children can collect benefits in their own right if they are under 18, or age 19 if they are still in high school.

A child can be considered in a person's care, and therefore the caretaker is eligible for benefits even if the child is not living with the survivor, as long as the caretaker is exercising parental control over the child under the Social Security guidelines.

Dependent parents also can collect a portion of the deceased's benefits if they were dependent on the breadwinner for support. There is a limit to survivor benefits that can be collected for the entire family, generally between 150 percent and 180 percent of the deceased's benefit amount. The amount is divided proportionally among the survivors.

"This is an incredibly complicated subject even for someone in the financial business," Parker says. "A financial advisor should refer to the Social Security office or Social Security Web site to make sure everything is being considered so that the client gets his or her full benefits."

-Karen DeMasters