It was never explicitly stated but I always got the impression the DS9-style uniform was more of a 'utility' uniform, kind of like a mechanic's overalls. In "Emissary" we see the Starfleet contingent arriving on DS9 in their TNG-style uniforms and later changing into the other uniform. No issue with them rolling up their sleeves, especially LaForge and O'Brien, who are both engineers. Riker just needed a better tailor.
Worf's baldric has always interested me. Obviously in TNG S1 it was identical to those worn on the Klingon TOS uniforms (because it was the same prop), then in S2 he switches to the metal baldric instead. I could buy that the TOS one was maybe an heirloom from an ancestor's time in the KDF, was the other one too? Or did he obtain/replicate a more modern one and decorate it with his family crest (talking of which, why does the crest change from Generations onwards, when it's still mean to represent the House of Mogh - until he joins Martok's house, at least)? Why switch to the heavier, more cumbersome version just after you've been promoted to head of security, when you may be expected to do more running/leaping around? We see it come off or nearly off several times over the years as the villain of the week shows their strength by chucking him around like a rag doll. And why does he continue to wear it over his Klingon uniform in "Redemption" when none of the other Klingons do, yet when he wears a Klingon uniform again in DS9, he doesn't?
