I just got my annual letter about social security benefits and, now that I am reaching the appropriate age, I ran the math. I was kind of surprised by the outcome.

If I had started receiving benefits at age 64, my monthly check would have been X. At age 66 it becomes X + $198. At age 70, it becomes X + $912.

I had looked at that part before and assumed it was to my bride's benefit to have me start at age 70. (She'll outlive me by decades unless she gets hit by a truck.)

But then I looked at the total amount that would be paid out depending on how long she lives, and that is where the surprise came. If I had started at age 64, the total would have been biggest if she lived to 80. If she lives to 85, she'll be best off by my starting at age 66. If I wait to start until I'm 70 she won't get the most in total until she reaches age 90.

I had expected when I started this exercise that the totals would be closer. And I have not done any present value calculations to adjust the amount. Present value adjustments would make taking it early even more attractive.

Something to think about for those of you looking at retirement.