Have I caught up to this week's material? If so, go ahead and read outside sources.
[When I have all day to study]: Have I studied 6-8 hours (42-56h/week)? If so, feel free to draw, compose, write, what have you.
[When I don't have all day to study, work a dayjob]: The above, but 3-4 hours (21-28h/week).