The U.S. Marine Corps found some interesting trends in reenlistments over the last year. Basically, the more time marines got to spend overseas, the more likely they were to reenlist. Marines are trained for war, and the prospects of getting into one appears to be a major incentive to staying in the Marine Corps.
There were some other interesting differences. First term marines (serving their first enlistment) were more prone to reenlist, the more time they had spent overseas. But only if they were married. Single marines were less prone to reenlist, the more days they spent overseas. Moreover, marines who spent no time overseas during their first enlistment, were less likely to reenlist than marines who had gone overseas. The differences in reenlistment rates were not great, but they were there.