In jazz, you ascend using the melodic minor and you descend using the melodic minor. Whether you revert depends on the chords the melody is harmonizing with otherwise you may end up being seriously out of tune just doing it automatically because that's how you practice it that way. Ultimately, it's not really useful to practice that way.

You should know those scales but only ascending. They teach you how to "plug holes" in the scale depending on the situation but how you descend is also likewise dependent (and, more often than not, it is the same way you ascended). Nothing graven in stone so why practice it as though it is?

It's funny because I'm saying, music has become too cluttered with crap that isn't particularly useful and sometimes wrong and people are arguing that I need to keep it simple. I guess my saying that there are easier ways to learn about music than the bloated holdovers taught in music even by people who should know better is not the same as keeping it simple.    Grishka seems to be the only one really getting it.