When I retired from the military we had two choices (well, my spouse had the choices, not me).
The first choice was to sign up for the military's Survivor Benefit Plan, with monthly premiums (before tax) of up to 6.5% of my pension (for up to 30 years) to fund an inflation-adjusted benefit of 55% of my pension for my survivor's life. Today that means I'd be paying $225/month for a survivor's inflation-adjusted annuity of $1900/month. About half of the cost of the policy is already subsidized by the federal govt, so it's hard to find cheaper insurance.
The "problem" with SBP is that you get one chance to sign up (before you retire), one chance to cancel (after two years of premiums), and then you're locked into 30 years of premiums until it's paid up. Of course if you're divorced or your beneficiary dies or you remarry then you get to change the terms. When you're retiring from the military at age 41, having a paid-up policy by age 71 for the rest of your spouse's life seems like a good deal. About 75% of military retiree's spouses (or other beneficiaries) take SBP.
http://the-military-guide.com/2011/04/11/survivor-benefit-plan/The other choice was to buy cheaper term insurance for some period. I never priced any of those policies but there are a number of military-friendly companies (like USAA) who are happy to underbid the rest.
We were already financially independent when I retired from the military, and spouse has her own Reserve pension coming at age 60. Worst case was that she could decline SBP, I'd get run over by a bus the next day, and
our her savings would have to last until her Reserve pension (and later Social Security) kicked in.
She decided that she'd rather enjoy 6.5% more fun while I'm alive than 45% less when I'm dead.
When she retired from the Reserves and it was my turn to accept or decline SBP, I declined too. She assures me that I will not survive her, although I'm afraid to inquire exactly how she can be so confident of that.
Our other choice would have been to buy term insurance for some period, like until we were eligible for Social Security. But we already had "enough" and insurance didn't seem necessary.