As you progress you'll run into fewer and fewer working pressure regulators, until you'll never see any more at all. Part of the mid- and late-game is figuring out how to depressurize safely.

Personally I like (ab)using airlocks and cockpits. Because of how the physics work, if you can safely depressurize a small area (or at least non-explosively), you can then use the doors between it and other areas to depressurize them.

Even if the area on the other side of the door is far larger than the one you're in, it'll still 'eat' all the air pressure. I don't pretend to understand how. :)

Another trick is to vaporize (not just cut) the small structural beams surrounding a wall panel, which creates a narrow gap that air can vent through without shattering everything.

Usually.

--sofaspud
--sometimes you'll run into load-bearing cockpit glass and trigger a reactor meltdown, but that's just a shipbreaker's lot I guess