The Army spends over $1.8 billion on permanent change-of-station moves annually. That’s 40 percent of what the Army receives each year to purchase weapons
warontherocks.com
That moving soldiers around stuff dates clear back to the end of the Civil War, to ensure that all the active Army units were as mixed as possible with people from every state in the Union.
But all the branches do it.
Navy rotates you every 3-4 years to a new unit, usually sea/shore rotations unless you're a SeaBee or Patrol aircraft dude. Start on a ship, go to a Squadron or Group command and have time to get some school in, go back to sea, now it's time to be an instructor at your specialty school, etc.
Air Force does it, working at a squadron, then to the depot, then another squadron, now teach, etc.
But okay, I think I can see how the Army might reduce moving people around. start as your basic grunt, get assigned to the same Brigade at battalion or Brigade staff or support company/battalion, go back to another unit in the same base once you're a sergeant, etc.
But part of the reason for moving people is to get them away from the units they were in, so they might have a chance to start over with people that didn't know the stupid shit they did as a new soldier that asshole command was never letting them live down. My first command master chief was like that. Never forgot a fuckup, and never let you forget one you'd made, either.
The rare few people I knew in the Navy that managed to stay in one location for any length of time were in very specific career fields and groups. We jokingly called it "Homestead Service" if you spent more than 3 rotations in one spot. Even knew of one guy in Hawaii that stayed there for a couple of rotations. He had to let his enlistment expire and make the Navy send him back to his home of record before they'd give him any job options but yet another tour in Hawaii. Apparently after your shore tour there you have pretty much done and seen everything in "Paradise" and you get a bad case of "Island Fever" and want to leave. Dude literally arrived home with all his household goods and walked into the local Navy recruiters office
that day to enlist again, just to be able to go somewhere,
anywhere other than Hawaii.
turns out some MOSs r crowded...some means allowing dual MOS qualifications!? compensation for concurrent qualifications.. yikes.. MP & Cav Scout MOS qualified troops as a backup capability would will always be necessary for Army contingencies IMHO. Temporary critically low MOS assignments w/ the promise to return to Cav & MP...
The problem is that
those horribly undermanned specialties will not want to give up their forced converts. It took a letter written by a couple of admirals to release one of my classmates from Subs to SEALs, for example. Subs are always hurting for people to double or triple volunteer for their programs, so they never want to release anyone. Even if the person is a screaming danger to themselves and others.
Have no clue how one dude made it through boot camp with as little muscle as he had. He was unable to lift an 80lb bag of stuff for the bridge from his toes to over his head so the next guy could grab it.
It took a massive amount of work to get him out.