Not to turn this into an AF vs Army argument, but I've often believed that the AF valued its people much higher than the Army (especially its enlisted).
Part of it maybe that we required longer commitments upon enlistment or commission, and part of it maybe that we have a larger ration of very technical/skilled people (hence the longer enlistments).
A lot of enlisted jobs in the AF, they could require a lot of education, hence a large investment and not as easy to replace as quickly, while (according to relatives) the Army saw a lot of more of its people as being, for lack of a better phrase, easily replaced.
You can't just replace somebody that works on and with nuclear weapons, and when you have weapons systems that are around 50 years old (B-52s, etc.) you sure as hell do not want to lose the institutional knowledge that senior NCOs accumulate.
That's not old, they are just doing an "avionics MID LIFE Upgrade" program now. My employer, and maybe me, are helping upgrade some of the maintaince trainers to the new configuration. The old girl has lots of life left. (The -H models aren't quite that old yet, only about 40, and the rest are in the boneyard)