How much does volume matter when breaking in amps and cables?

In response to geoffkait's reply above; Some manufacturers, like me, actually do send "broken-in" product to our shows.  Sometimes if you hear something that isn't good at the beginning of the show and doesn't get better, then that's just a result of poor setup and not spending enough time evaluating the room.  

However, there are caveats to that as well;  Sometimes as a manufacturer, when you're trying to fill as many seats as you can, in the room you could afford to be in, you might sacrifice the better sounding wall in order to get more people in your room.  It's a trade off we all have to decide on as we're setting up, particularly in smaller rooms where we don't have much space.  We have to make the choice, do we sacrifice sound at the expense of making it more comfortable for the attendees, or do we go for the better sound and have people complain that they couldn't get a good seat or get into the room to really audition the system or people were always walking in front of them? 

Also, we can end up short on cables or there wasn't an outlet where we were told or thought it would be and can end up arranging everything based on those limitations.  We have to take a lot into consideration at shows like Rocky Mountain Audio Fest...just FYI...

Absolutely none at all. Zarathu is right. There may be some speakers that loosen up in the bass after a few hours but that is about it. This myth got started by dealers telling their customer who were not sure that they liked a new piece of equipment, "you just have to let it break in." In a few weeks they get used to the sound and everyone is happy but in reality nothing changed. This break-in myth is the ultimate BS of all BS. The manufacturers do not want to say anything against it because the they do not want to alienate potential customers plus they can always use the break-in excuse. In reality it is not your equipment breaking in, it is your brain breaking in.

Oh, which means in geoffkait's case I have no explanation.

Did you perform surgery on your own brain, Doc?

It doesn’t matter at all, as breaking in cables and amplifiers is a myth invented to reduce returns