Stupid?? Phono Pre question...break in

I hope this isn't as stupid as it sounds...

I have a question on phono break-in. I have a Slee Era Gold, and it mentions that after unplugging, it will take about 72 hours to warm back up. When they state 72 hours, do they mean just keeping it on and plugged in for 72 hours, or actually playing music through them during this break in time?

Thanks,
Paul