I can’t argue with that statement; it is the current trend, and not the trend for every military on earth, or throughout history. But even so, many militaries did create regiments, and people joined that regiment, and moved up through that regiment, never transferring outside of it. Just as, in early days of sailing; many ships would hire on a crew, and then use that crew for the entire voyage, and only recrew after the voyage was over, and a new voyage was being set up. So, in that aspect, I would suspect that you wouldn’t have crew transfers. But, I would argue, that most of the time, the reason why there wasn’t transfers, was simply that it wasn’t feasible to have them. In the early days of sailing, when a ship left port, it was impossible to change the crew, or have crew members transfer out; because there was no way to move the personnel around. Even so, I suspect, that some history buff will point out, that when ships passed each other from the same nation, that some people did transfer. Just as I suspect, that some officers would transfer from one Army regiment to another regiment, when they weren’t engaged in hostile territory. The reason why today’s military conducts transfers, is because it is possible to do so; and in the Star Trek universe, they have the capability, unless they are on a deep space mission, to conduct the transfers. Even Kirk, on his five year mission, went past star bases from time to time; I suspect to restock on redshirts….LOL I guess the bottom line; I can see both arguments; and although it may not be the best model for a deep space exploration in Star Trek, like Voyager; I think it would have be a good model to pursue in a show like DS9 or TNG.