My 1 cent worth as almost an OCS graduate. I believe that during the Vietnam conflict, a lot of rules were relaxed to have bodies to through into the conflict. One classmate of mine was 18 years old and his parents had to sign a waiver so he could go to OCS. Can you imagine a grizzled old master Sgt, taking orders from him, especially in the heat of battle? BTW, 50 percent of that class did not make it home from Viet Nam. And 65% of first and second Lieutenants did not make it back. It is hard to maintain esprit decor when there is no continuity of service. I think the Marines maintain it the best because of being a smaller unit. The USAF would be second. My brother served for 23 years on active duty and another 25 or so at Wright Patterson and he served off and on with the same people.