Why no “Break in” period?

Oregonpapa, that is a mechanical device where that can be expected and I have personally heard this with several but not all cartridges. My Clearaudio Da Vinci was so shrill initially that I had to make a new EQ curve for it and I was mad as a viper but in perhaps about two weeks things started sounding dull so I switched back to my normal curve and everything was wonderful. This was objective because I could compare the sound with my other turntable.
However as far as electronics are concerned they do not break in and anyone who believes they do is deluding themselves. You even have millercarbon comparing them to wine. He is wonderful at composing long posts that say absolutely nothing. 
Andy, there are extremely few things that age gracefully. Maybe the occasional Ferrari that has not been driven. Even wine goes bad if you leave it too long. 
Rodman, the last thing I am going to do is trust your ears or anyone's ears including mine but if you want to chase your tail deluding yourself into thinking you heard something and piss money away on silly stuff, wonderful. It is still a free country and you are not hurting anyone else. As a matter of fact you are supporting other peoples jobs. Keep it up.

Enjoy your swirl.

All this talk makes me laugh. Has anyone here been to an audiologist ("hearing doctor") I doubt it. If you do go to one, you will probably learn that your ears and your hearing are basically no different than anyone else around your age. A few will have a little poorer hearing and some will have a little better but none will hear outside the realm of human hearing, like bats and dogs. I worked st a Detroiy auto plant. All employees had to take a hearing test every 6 months,  no ex exceptions. Almost all came back normal.

People that claim they hear things that others dont are probably confusing familiarity with sensitivity. For example if you hear something once or twice a day for years and then one day it slightly changes, that is familiarity, not sensitivty.

The most objective test of hearing that I have witnessed was a test administered by a Proffessor of Music at at a university niversity in NY who is an instructor of guitar. He took a student that has perfect pitch (been tested) and had her favorite songs (she was familiar with) played through high end headphones and tried to distinguish between vinyl and CD. She failed, her percent of correct responses was no higher than the success rate of someone who guesses without even listening.  The test was not exhaustive, I would have done it differently, but it did convince me that those that claim they hear what others dont, are wrong. I think Mr. Carbon is confusing familiarity with sensitivity. For those Interested, the test was published by Rock Beato on YouTube so you can watch it yourself and come to your own conclusions.

geoffkait, what in god's name are you talking about? A single experiment can be perfectly valid if done correctly. "Sorry pal" is offensive. Do you really need to be as immature as rodman? All you have to say is that you have faith (The Cure) that "break in" exists for electronics and no mater what you tell me I am going to believe in that. I can live with that and I know for a fact prof can also. Then we can just discount everything else you have to say as a religious moment and be done with it.

Markpop, I am a doctor and I do have a complete computerized audio logic set up. We have to test hearing for certain professionals and thank you. You are quite correct. I meant essentially the same thing using the analogy of a cat meow vs a dog bark. I do know of that test and I wish he had done it on a few audiophiles using high res vs CD res. Vinyl I think most of us could pick up by the back ground noise.