I was planning to shut down during the traffic peak. That seems the obvious choice if you want to save the most people's time.

I think that it might depend on when the most traffic peak is. I know that I am most productive around the afternoon, so if it was shut down then, it might make a difference in my productivity. If it was shut down around 9:30-11:00 p.m., it probably wouldn't do much for my productivity because I'm not usually doing much work anyway at that time. This would of course depend on traffic peak and where most of the users were located.

And annoy a whole bunch of others.