Married women may have the option of claiming benefits based on their own work record or 50% of their spouse's benefit. For couples with big differences in earnings, claiming the spousal benefit may be better than claiming your own.
Divorced women may be able to receive benefits on their former spouse's record—even if the spouse has remarried!—but only if: the marriage lasted 10 years or more; the claimant is unmarried and age 62 or older; the former spouse is entitled to Social Security retirement or disability benefits; and the benefit you're entitled to receive based on your own work is less than the benefit you'd get based on your ex-spouse's work.
Widowed women are eligible to receive their late spouse's Social Security payment as a survivor benefit, provided it's higher than their own monthly amount. The surviving spouse can claim the higher monthly benefit for the rest of their life. So, for a couple with at least one member who expects to live into their late 80s or 90s, deferring the higher earner's benefit may make sense. If both members of a couple have serious health issues and therefore anticipate shorter life expectancy, claiming early may make more sense.