But what could be the most important information for those who joined up after 2006, or will do so before the end of 2017, could be the data it contains on the new blended retirement plan that includes both a pension and contributions to the government's Thrift Savings Plan.

Those who enlist in 2018 and later years will automatically go into the blended system, but those who joined earlier—but after 2006—will have to decide whether to stick with the old plan or go with the new.

There's been a fair amount of criticism of the new plan, although it does provide some benefits not available under the old system—for instance, a retirement benefit to servicemembers who don't stay in long enough to retire.

In the private sector, of course, people changing jobs take their retirement savings with them; in the military, that hasn't been the case, and those serving less than 20 years leave with nothing.

The new plan offers options—not only for that, but in providing choice of a lump sum or a monthly benefit at retirement.

But there are disadvantages to the new plan, too, including the way benefits are calculated. Actuaries have warned that the new system calculates lump sum benefits in a way that actually makes them worth considerably less than those in the private sector.

It's not just about the new retirement plan, however; the guide covers other military benefits, investing, warnings about financial fraud, home buying and selling and financial resources for military families. The guide is available online.