eqipment on 24/7?

Not trying to be a wise guy, but if it only takes a 1/2 hour to sound optimum, why bother leaving it on 24/7?  Is there a sonic difference?  If there isn't does that mean that we're all leaving our gear on to be able to 'save' a 1/2 hour?  Here's the thing, I've tried both ways, and I'm hard-pressed to hear the difference.  So, even though I've been at this for decades, I'm left with the old basic, rookie insecurities.  Namely, is my gear good enough to hear the difference?, is my hearing?  I'm curious to read more!;)

My old McIntosh MC2100 originally didn’t have an on/off power switch so it was on 24/7 but it sounded really good.

I used to leave all my gear on 24/7 with nothing but positive results.

With my Kinki X-M1, I leave it on standby and it works just fine. The reason is, my media stand is tight on vertical space and the Kinki will 
heat up to where it actually gets hot.

Others who have theirs out in the open have no problems. So, it all depends.

All the best,
Nonoise

My SS phono/pre 'snaps' into focus after about 15 minutes, and gets better for an hour. Same for my higher end Nak cassette deck.

My amps (SS Class A) are much slower. Listenable after an hour, splendid after 10.

Both EmmLab Dac2 and Lyngdorf 2170 sounds smooth and more refined after 24 hours warmup.

Thus I leave all the Dac 24/7 on including Dave Chord and Mscaler.