Back in the old days! One couldn't make Airman first (1961-65) on their first enlistment if they were in maintance (463rd FMS). We had a lot of open E-4 thru E-6/7 slots, but they were filled by by Airman seconds. Flight crews were given first priorty when it came to promations.. Almost all airman seconds held a 5 level rating. As an airman second, with a 5 level rating, one could sigh off a Red Diagional in the aircraft log.
Airman Thirds and Airman seconds without a 5 level rating, didn't have to pull maintenance duty on weekends, holidays or nights.
So much for the old days! OH, by the way, none of the deployments I went on were recorded. As such, the only comendation I have, is a good conduct medal! I served and it was the best part of my life. Too bad I had to mature a little to realize it.