It is a workout for my creative mind. 45 minutes = 20 minutes sketch, 20 minutes color, and 5 minutes edit. Just like a timed write, this is how I will practice.
I've allowed myself roughly 2-10 minute interruption. These are not counted due to my distractibility. Subtracting the distractions equals the 45 minutes. Do not count my hunger, thirst, and urge to pet the cats.