I recently answered a couple of questions on calculating the amount of a Reserve retirement for both Final Pay and High Three pay systems. If you’re eligible for a Reserve/Guard pension then let me repeat the questions & answers so that you can confirm your own math. If you’ve had a different experience, please post about it in the comments! I’ve read the references and checked them with an expert, but I haven’t personally gone through the process.
When you’re in the Reserves or Guard, your time toward a pension is credited on two factors: the number of points you build up, and the number of “good years” you’ve completed. You accumulate points for drill weekends, active duty periods, and some special circumstances like online/correspondence courses or funeral honors detail. Each service is a little different in their point calculations– for example a Navy Reserve drill weekend awards two points per day because a Reserve weekend counts for four drill points.
Points accumulate from both active duty and the Reserve/Guard system. Each day of active duty counts as one point. Each drill counts as one point, as do the days of active duty in the Reserve/Guard for training or mobilizations. It’s possible to get points for other purposes but they’re generally limited. (It’s possible for officers commissioned from NROTC to receive points for the days they were on active duty for midshipman summer training, but they’ll need to supply the documentation.) You’re also limited by the number of points you can get in a category– you can’t do 52 drill weekends in one year and get points for every one. Of course you can certainly be mobilized during a leap year and receive 366 points of active duty.
A “good year” ensures that you show up each year for a certain minimum amount of work. Again each service has their individual requirements, but generally if you show up for drills on at least 10 of the 12 months (or complete enough other assignments) then you’ve met the intent of a good year. You may be required to earn a certain minimum number of points within 12 months, and to maintain your mobilization readiness (like completing the medical checklists). When you do that, you’re credited with your “good year”.
This status is tracked in your service’s Reserve/Guard databases, and you may be issued occasional updates. Every year you can earn a certain number of points and get a “good year”. However you’ll still have to verify that your service correctly credits you with that accomplishment.
You’re considered eligible for retirement when you’ve completed 20 “good years” of service. (But of course you can usually choose to continue to serve.) If you have a combination of active duty and Reserve/Guard duty, then your active-duty service time counts toward the 20 good years. There are also special circumstances (mainly medical) when you may be eligible to retire before reaching 20 good years. However for purposes of this post we’re going to assume that your retirement eligibility is based on the main requirement of 20 good years.
When you reach 20 good years, your service will eventually formally notify you that you’re eligible for retirement. (You may still have to finish other obligations like an enlistment, a minimum time in rank, or a set of orders.) When you complete those requirements (or have them waivered, or agree to retire at a lower rank) then you can apply for retirement. The key to your retirement is that “notice of eligibility”.