Because I'm an old, retired guy, I can play anytime of the day, but it usually is the afternoon, around 12 noon.
It's even better if I'm still in the same tournaments, and it's dark out...lol.
Seriously, though, I usually set out a schedule for myself at 11:00 am, by looking at the freefolls for the day, and any other tournaments that catch my interest.
If I play at night, it's usually around 7pn, and those are almost always buy-in tourneys.