Liz Weston

Dear Liz: My ex-husband is 13 years younger than I. We were married for 10 years and he earns more than I do. If I start drawing my own Social Security benefit at age 70, can I switch to his benefit when I’m 75 and he is 62?

Answer: Normally when someone applies for Social Security, they’re “deemed” or assumed to be applying for all the benefits for which they’re eligible. If you’re eligible for your own retirement benefit as well as a divorced spousal benefit, for example, you would get the larger of the two amounts. You wouldn’t be able to switch from one to the other later.

There are a few exceptions to this rule, however, and your situation is one of them. You won’t be eligible for a divorced spousal benefit until your ex-husband reaches minimum retirement age (62). At that point, you would be eligible for 50% of his primary insurance amount, or the check he would get at his full retirement age, which is currently between 66 and 67. If that amount is larger than what you’re receiving, you could switch.

If you’re going to switch, though, you may not want to wait until 70 to apply for your own benefit. Delaying makes sense for most people, because they’ll live past the break-even age in their late 70s when the larger value of the delayed benefit more than makes up for the smaller checks they pass up in the meantime. If you switch at 75, though, you won’t have received your own benefits for long enough to make up for bypassing the smaller checks, says Dr. William Reichenstein, head of research at Social Security Solutions.

Deciding when to start Social Security can be tricky even in simpler situations than yours, so consider using a site such as Social Security Solutions or Maximize My Social Security for advice on when to claim.