Speaker Break In...? Or listener “Break In”?

prof   I agree.  It's like a car salesman.  If they can get you inside the car and take it for a test drive, or let you take it home and drive it for a couple days, a sale is more probable.
I do think there may be a slight break in for speakers, but I also wonder how much we adapt to the new sound.  It would be interesting to compare a used pair of speakers with a brand new pair on the same system and see if you could tell the difference.