"Assuming health is good, married couples should hold off until at least full retirement age (66 or 67) before taking any benefits," Koehnen says. "Taking it before this time will result in a permanent reduction that could mean missing out on significant dollars, depending on how long they live. I recently ran an analysis for a client, which showed that if they both waited until full retirement age and ultimately lived until age 85, they would receive over $150,000 in additional benefits."

For healthy couples who would like to maximize their lifetime payout, Koehnen recommends delaying the collection of benefits -- with the exception of Social Security spouse's benefits, as you'll read below -- until age 70 if possible.

3. Delay Social Security benefits for the higher earner

If one spouse was the major breadwinner for the couple, that spouse may want to delay receiving monthly retirement benefits from Social Security longer than their partner. Doing so can help guarantee that the surviving spouse will collect as large a benefit as possible when the other dies.

"The spouse with the higher monthly benefit should postpone collecting Social Security as long as possible, but not beyond the age of 70," says Michelle Tucker, a certified financial planner at Tucker Wealth Management in Honolulu, Hawaii. "The object of postponing is to maximize your benefit and this higher benefit will be paid to you for life and continue for the life of your surviving spouse."

4. Consider a file-and-suspend approach ...

Using a file-and-suspend strategy is one way couples can reap an oft-overlooked perk: Social Security spouse's benefits.

For example, if both spouses are eligible for benefits and one opts to file and suspend while the other doesn't file at all, it allows the nonfiling spouse to claim a spouse's benefit as both of them continue to let their regular benefits grow. If the couple intended to delay collecting anyway, this monthly spouse's benefit effectively equals free money.