"Why do you measure everything in those old units?"

Translation: Proč všechno měříte v těch starých jednotkách?

[andrew_lim]

Is "in" unit measurement always expressed with v + locative and not instrumental? My intuition had me guessing "těmi starými jednotkami" but I seem to be wrong - I'm curious if there's better intuition or if I should just remember this pattern. Thanks!

[VladaFu]

Yes, instumental is used for the measuring instruments, not for the units.

[svrsheque]

it is possible but 2-3 orders of magnitude less frequent. we can consider recognizing it.

[andrew_lim]

VladaFu's explanation is good for me. Personally I'm of the school of thought that phrasings that are technically right but are uncommon, odd, or just not done in practice should be rejected (and conversely that technically grammatically incorrect phrasings that are common in practice should be accepted).

I expect you deal with pushback from people who feel hurt when their technically correct answers aren't accepted, so just throwing my two cents out there that I don't really feel that way :)