I will usually try to get your pic to you in 3 days, but it may take as long as a week, especially if you've requested multiple characters or a more complicated picture.
I try to communicate a lot with my customers, I want to draw you something you'll love, not just like. Thusly, I'll need to see the subject of my picture if it;s a portrait of a person or OC, ideas on what you want them to be wearing and doing, and an idea of the color scheme.