How to evaluate amps that are not broken in?


I'm expecting to demo Belles and JoLida amps next week at home, and both units are new. Can I assume that if I like the sound of an amp now, I will like it just as much after it's broken in? How does one account for this variable when trying to decide if a new piece of gear will be synergistic with one's system? Thanks!
stuartk
they'll only improve so yes, if you like them now, you'll like them more later. my very unscientific guesstimate would be that they'll improve by about 10% - not enough to radically change your opinion of them, but possibly enough if you're on the fence.
OK, that's encouraging, Musicslug. I realize this is very much a newbie question, so I appreciate your taking the time to respond.
Break in is something that is highly debatable. Considering all of the variables that are at work EACH time you sit down and listen it is very difficult to attribute any gains directly to break in.

However, people that do believe in the theory seem to agree that only good things come the more the component is played.