I did just under 2 years as an OS and AB before being picked up for officer training. To be completely honest the most useful part of the experience was the fact that as an officer I was wise to all the scams and tricks the plugs, problem children, Fu*kups, sick bay rangers etc; used. Those guys and gals are maybe 10 % of the people you are responsible for, but generate 90 % of your work. Most were use to treating junior officers like mushrooms, but they quickly found that did not work for me. Funny enough a significant number of that lot started asking for transfers, a process I did not discourage....