Earlier quoted context omitted.
The greatest asset the US has built up over the past twenty or so years fighting in Iraq and Afghanistan is a reserve of soldiers with real world military experience. The average term of enlistment in the USA military is 15 years, 11 years for officers. So that experience gets lost quickly unless we keep getting embroiled in new wars.
There's no way the average term of enlistment is 15 years. Very few people choose to re-enlist after their first term, or are even allowed to. In 2016, there were almost 200k Marines, and they were struggling to get 10k people to re-enlist after their first 4 years[1]. https://www.marinecorpstimes.com/news/your-marine-corps/2015...
The average length of enlistment for U.S. military personnel is just under 15 years for all branches. The average service time for officers is a bit less, averaging about 11 years. The U.S. Air Force has an average enlistment time of 14.7 years. Oct 4, 2017
The referenced URL is:
https://classroom.synonym.com/beyonce-curls-8729.html
(yes, that "beyonce-curls" URL is the right one)
Surprisingly, it does include references, but only one of them still exists, which backs up the 11 year number for officers, but not for general enlisted:
https://www.pewresearch.org/social-trends/2011/10/05/chapter...
The average officer in 2009 had been in the military nearly 11 years, slightly more than a year longer than the average in 1973.
The pattern among enlisted personnel is more complicated. The average length of service for enlisted personnel rose from 5.8 years in 1973 to a peak of 7.5 in 1994 and 1996, but then began drifting downward and now stands at 6.7 years.