there are also the GMIA moments that happen in audio when everything is just working prefect and the system sounds great. I believe that some may mistake this or perhaps just call it break in. I think three to five days should be sufficient time to take a listen and hear what something does. If it takes 500 hours , in my personal opinion, to sound good , that will never happen with me, since it will be long gone.As much as I believe I've heard additional improvements with equipment >200 hours break - in, I can't help believing some if not all of the improvement is confirmation bias for us all. Without an A B X compare, we're all just giving our subjective opinions.
Getting used to something is not the same as break in , nor should it be.
When someone told me once that a footer takes like 300 hours all I could do was laugh. I have a sale of some older bridges this weekend and they can be had cheap!