Well, maybe an hour or two.

Anyways, speaker break-in isn't like breaking in an engine where you have to baby anything... and (mercifully) not like breaking in a rifle barrel which is such a pain I'm thinking about not believing in break-in any more.

Play. Enjoy. You might notice the sound seems to improve over the first few hours. General consensus though is that your mind is adapting, not the speakers changing.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8