They stay captains even a shorter time than we do. I was actually a captain for 11 years total (got off AF and into the reserves at EXACTLY the wrong time).
Colonel, USAFR
So did I. My third reserve CO (well IDT detachment commander) said I had the longest time in grade of any 1LT in the Air Force Reserve, when he announced my promotion to the detachment. Don't know if that was true, but with a 4 year break in active reserve status, and a year in the ANG, I had been a 1LT from June of '75 until 31 Oct '84, although I got some back pay and DOR adjustment to the time I was first eligible, rather than from when the promotion orders where issued.. IMy official DOR as a Captain was 20 Dec 83, . So I was a 1LT for about 8 1/2 years, but carried the rank for over 8 years.