Military organizations have always had a problem with too many officers, and too few officers who were any good. One solution to this problem has been practiced by the United States for the last 50 years. Officers and NCOs must either be promoted, or leave the service. The system is set up so that everyone can serve at least twenty years. But after that, it's truly up or out. Only the most senior officers and NCOs can serve the maximum thirty years. This worked for a while, but over the last few decades it has become obvious that the many new specialties don't provide sufficient room for promotion. For example, the air force promotes some 90 percent of captains major, but only 45 percent of those captains make it to colonel, and only two percent to brigadier general. Those who don't make it to colonel have usually hit the twenty year mark and retire on half pay. But many new technical specialties (computers, networks, electronic warfare) have critical shortages of qualified people inside and outside the military. Yet because of the "up or out" policy, the military is forcing trained technical experts to retire because their specialty does not have enough senior slots. What really bothers the military is that these guys promptly get hired by a technical consulting firm at twice what the military was paying them. Then the military, short on techies, goes to these consulting outfits and hires needed experts at much more than they were paying the people they forced to retire. It's been noticed that many nations, like Britain, allow qualified officers to stay in the same job (without promotion, but some pay raises for seniority) for decades. The U.S. army has long adopted a similar program by creating a special class of officers (Warrant Officers) who can work their specialty for decades. But not everyone wants to be a Warrant Officer (who are not supposed to command troops). So the promotion system is up for modification, to allow "career majors" and such. The air force has already been moving in that direction to solve it's worsening pilot shortage. Pilots are offered longer periods in cockpits, but fewer opportunities for promotion. Most pilots find this a most agreeable arrangement.