When I was in the Navy I knew a couple of guys that had been in the Marine Corp or Army before joining the Navy. Another guy was drafted into the Army during Vietnam. When he got out of the Army he enlisted in the Air Force, did one or two hitches and got out then a few years later joined the Navy where I met him. The other day I ran across a story about a guy in New Jersey, gotta see if I can find it again, anyway he lied about his age at the beginning of WWII to join the Merchant Marines. Don't recall how long after that he used his Merchant Marine paperwork to enlist in the Navy. Took about a year for the Navy to find out he was underage at the time of his enlistment so they kicked him out.

Apparently he was now old enough so he enlisted in the Army Air Corp and flew in bombers during WWII. He was discharged at the end of the war but when the Korean War started he joined the Army. IIRC after the Korean war he did something for a year or two then got into the Marine Corp. Seems like the article said he retired from the Marines and went on to do something with aircraft in the U.G. Coast Guard. I'd say he was pretty dedicated cause I can't think of any branch he missed serving in.

Also got to wondering about special forces and found one guy who was a green beret, got out of the Army and joined the Navy and became a SEAL. While he as in the SEALs the Navy sent him through the Army Ranger school. I always figured some special operations guys might try different branches but I guess other than the Air Force PJ's and Marine Recon this guy had 3 of the five that I consider SF covered. I guess if you have what it takes to make it in one you pretty much have the tools to make it through any of them.