Stand-by on Mark Levinson products

My system: ML 331 power amp, ML 32 preamp, ML 31.5
CD transport, ML 36S D/A converter. I can only listen to
music during week-ends and I was wondering if it's better
to leave the system in stand-by all the time. Only the 36S
hasn't a main switch and when connected to the electric outlet it
can only be in two modes: "on" or "stand-by" (blinking led).
31.5, 32 and 331 (in the european version) have a main switch
so they can be switched off even if they are plugged to the
electric outlets. Is it true that take off the power
completely when the system is not in use shortens the life
of the components? I know that the system performs better
when is warm and I put it in stand-by mode few hours
before the listening session. I think that leave the system
in stand-by for 4/5 days (being sure that I won't listen
to it) can wear off my components more than put them in
stand-by few hours before the use.
Am I wrong?

Thanks a lot in advance.