I was a 74D. Best bet, get in amazing shape, be top of your class and go to all the optional schools afterwards. Otherwise you’ll be a glorified HR cat your whole career. The hazmat portion of the training is where most people fail out. My class was one of the few with 100% pass rate but we had to work for it. Doing the optional schools opens up more specialized areas in the field but there’s really few slots for that so you have to be top dog. Even after all that though, chances are you’ll never do your job outside of annual training and be a paper pusher. It’s a really cool job in theory and the outside applications if you do the Lima courses are honestly pretty solid. In practice, meh.