Trek is entertaiment, so when it comes to costuming the real world need not apply. The concerns of a TV show or movie is different than that of a real military. TOS had four different uniform types (five if you count the pilots) The black collared shirts, jump suits, dress uniforms and the wrap arounds. It wasn't unusual to see two types together. I think the second TNG uniform popped up on DS9 from time to time. So I look upon the DS9 uniforms being in the same "group" as the TNG ones. Sort of like when my dad was in the Aiir Force. He usually wore his kahkis, but on occasion he would dress in his blues or fatigues.
More often then one might think. We just recently switched to using ACU's over the whole of the US military, some units still being phased but for the most part its done. And they are already talking about the next design.
True. I was in Air Force ROTC when the USAF changed its standard blue dress jackets in use since the 1950s and 60s to remove the breast pockets and buttons and a couple of other features, streamlining them somewhat. And since then there've probably been other alterations I'm not aware of.
Actually, this was stated by the producers. There was an expectation that the toy licensees would have regular "new stuff" to release, otherwise there was no need for them to extend their licenses.
I guess in a multispecies alliance/union like the Federation you'd get some races wanting different uniform styles from time to time and Starfleet would change them based on a majority decision or something.
^I guess everyone in the Federation was pleased with the TWOK style uniforms for about 80 years, then!
Really? So all the soldiers I saw from different branches while I was stationed at FT. Gordon weren't wearing the Digital Camo? You're right, ACU is Army Combat Uniform, but a rose by any other name and so on and so forth. The point of my statement is that while the digi-camo is fairly new, they have a new style of combat uniform they are currently testing and talking about making the standard.
Yeah, they seemed to be IT from about 2277 until 2350 give or take. Jack Crusher was still wearing the maroon KHAN jacket as late as his message to his newborn son in 2349.