Equipment Warm up, but What About Listener Warm up?

Absolutely! Behind your ear drum are three little bones called ossicles.
Attached to one of them, the Stapes is a little muscle called the Stapedius. As sounds get louder this muscle tightens and decreases the ear's sensitivity protecting you from louder volumes. It also changes the ear's frequency response. It is always good to start at moderate levels before turning it up to a realistic volume to let your ears adjust.  

Cartridges do break in but I have never heard one warm up. Tube phono stages may need a short warm up period. I keep mine on permanently so there is no warm up period at all for the phonograph

@geoffkait , I thought you were warm and fuzzy anyway.

I've noticed that during long listening sessions, say at the three-hour mark, the system seems to reach out and the sound starts to envelop the room, including me. Do the electronics continue to warm up even further after several hours? Or, maybe it's the Vodka. 

Frank

I’ve noticed that the music sounds best if I’ve had a good day, everything in my life is going well, I’ve exercised pretty hard that day, I have nothing left to get done that day, and it’s night time.  If all of these things come together, it’s usually a recipe for a good listening session. 
I’ve also noticed that its best to take a 10-15 minute break every hour or so from the music...

I’ve also noticed that I can pick up more detail in the music at low to medium volume levels.  It’s not such an onslaught of sensory overload that I sometimes get at higher volumes, yet sometimes high volumes are whats needed to get me fully engaged in a musical experience.

I also like to listen first thing in the morning (or even if I’ve woken up in the middle of the night...low low ambient noise is a plus) when my ears and mind are totally fresh.  
I even tried wearing shooting ear muffs (I know, I’m strange) for 30 minutes before listening in order to “prep” my ears.  Akin to closing your eyes in the dark and picturing the darkest black you can, then reopening them and being able to see much better.  I didn’t notice much of an improvement doing this particular method.

Last way I warm up my ears is with routinely cleaning them thoroughly with hydrogen peroxide and a steady stream of warm water to help loosen / soften ear wax buildup.