Is it the beer or do speakers/electronics really need some extended warm-up period?

Geoffkait, doesn't matter, both are the same futile activity, horridly nebulous and fraught with subjectivity. Split them, merge them, either way they are useless. I'm a cable proponent, but that's different in that when I swap a cable I'm hearing the change immediately. What's being discussed that I find impossible is the notion that humans can accurately hear changes to gear over hours, days, weeks, months, etc. The belief in that is predicated up on the arrogant concept that humans have more consistent perception of what we hear than equipment has consistency in playing it back. That's laughable. 

I showed that the entire affair, including the concept of component burn in as well as purported benefit to warm up, is a waste of time and energy. The moderators here have a problem with me pointing to my writing, as though I'm somehow benefitting from it (even though I'm not paid), so they will pull a direct reference to it or I would post it. You'll have to do a search for my name and the phrase "burn in". Having actually conducted comparisons and finding no difference sonically between both new/old and warm/cold systems at the same time, I have little regard for promotion of either one; they are summarily a waste of one's time. 

Feel free to disagree, but I'm not interested in extended discussion of it here. I wrote my discovery and conclusions for all to read. 

If your gear is so thermally unstable it is crap. Fortunately, that is very rare - or you are delusional.

@douglas_schroeder I actually agree with part of what you’re saying, maybe even most. I agree to the extent I believe it’s quite difficult to keep track of the sound of one’s system over an extended time if one is trying to keep track of the progress and conclusion of the break in of a particular thing, whether it’s a fuse, a capacitor, a cable, whatever. I say that because there are too many variables at work, even if the audiophile doesn’t do anything at all, just sits there like a bump on a log, and doesn’t touch anything at all during that entire time. Now, I don’t know about anyone else but I don’t think I ever met an audiophile who was not (rpt not) constantly fiddling around and or replacing something. So it doesn’t make sense anyone can keep track of how something breaks in. It seems like something is ALWAYS breaking in. Hel-loo! And it doesn’t make sense someone comes to the conclusion that a capacitor takes 500 hours to break in. Give me a break!

Warm up is a horse of a different color. I suggest listening either very late at night or very early Sunday morning when the weather is nice and dry and sunny with high pressure. Then you will hear what your system really sounds like, without all the usual distortion. It’s no wonder folks can hear anything, there’s too much distortion during normal business hours to hear much of anything. Cut me some slack, Jack!

no need to recall a sound quality for days or weeks

simple to test with 2 identical units - one can be 'burned in' and the other not

have a friend swap them a few times and don't peek

If they need such a warm up, they are a truly bad design.