red wrote:
Are shut-off valves the last task in a plumbing job? If not, how do
you get the chrome trim (escutcheon?) between the drywall and the
valve? If so, how do you keep from trashing the painted drywall when
soldering the shut-off to the stub?

Yes, the angle stop fixture shutoff valves are usually the last task in
a plumbing job. IANAP, but what I have seen with copper piping is a
capped stub or closed pipe end is installed prior to the drywall through
which it protrudes. Then when the finish plumbing is done after the
painting, cabinets, or tile are done when the stub is cut off and the
escutcheon and angle stop valve are installed with compression fittings.
No soldering involved at this point.