I'm not sure why someone would stay in the IRR past receipt of their NOE unless they felt that they had a really sweet gig-- or a burning desire to complete every correspondence course in the catalog.
I was on IRR and standby for years. Part of that time, I was fulfilling commitment to remain aligned with the reserves that I incurred as long as I was receiving small yearly payments as part of my voluntary separation (from active duty) incentive. Then I stayed on just because I figured they'd only call me up if something really bad happened. I wasn't getting any points because I wasn't doing anything. Then they moved me to the retired reserve, even though I don't have enough points to get military retirement. I'm sure I could get off of it, I just never bothered to do so.
There's a fine point buried in my commentary which causes a lot of confusion in the Reserves/Guard, and I get the question all the time on The-Military-Guide.com.
You were in the IRR because you had a military commitment. No issues there.
However once anyone in the Reserve/Guard is eligible to
retire (20 good years), the only reason they would want to stay in the IRR would be if they wanted to pile up more drill points before applying for retirement. The IRR is a painful way to earn points & good years because you can't go on active-duty orders and your activities are largely self-directed. Some can achieve satisfaction at knowing each point they earn on a correspondence course is worth another 30-50 cents/month in military pension for the rest of their lives. Others wonder why they're working so hard for so little and whether their time could be better spent on more lucrative ventures.
Many servicemembers stay in the IRR after they're eligible to retire because they don't understand how the Reserve/Guard pension is calculated. In my spouse's unit (and in many questions on the blog) people had received their Notification of Eligibility letter and could apply for retirement, but they thought that they had to keep drilling for the next seniority pay raise. For example, an O-6 with 22 good years (and their NOE) didn't care about drill points but wanted to retire as an O-6>26 (a healthy pay raise). They thought that they had to stay in the IRR (or in a drill billet) in order to achieve that status.
However the Reserve/Guard military pension is calculated using the pay tables in effect at the date when the pension starts, and with the assumption that the servicemember had been on active duty for the entire time. This usually results in the maximum longevity pay for their rank. All that O-6>22 had to do was file for "retired awaiting pay" status, and in four years their pension would be calculated at the O-6>26 pay table column. In another four years their pension would be calculated at the O-6>30 pay scale.
Most servicemembers join the military before age 30 and most start their pension at age 60, so the vast majority of Reserve/Guard retirees have a pension calculated at the ">30" column in the pay tables. Even if someone joined the Reserve/Guard at age 17, racked up 20 good years, immediately filed for "retired awaiting pay", and didn't start their pension for another 23 years, that pension would be calculated at the pay tables (and their longevity) in effect when they turned age 60. In other words their pension would enjoy the benefit of over two decades of pay raises (and longevity raises) before they even got their first check.
Of course when you're in the IRR or in "retired awaiting pay" status ("gray area") then you're subject to involuntary mobilization. But most people think that the payoff is worth the risk.
I completely understand why someone would stay in the IRR to earn good years for retirement (or to complete an obligation). Once they've received their NOE, however, it's usually far better to file for "retired awaiting pay" and stop earning points the hard way.
