I use Arches watercolor paper when I paint, which is really high quality paper. A pad of 10X14 paper with only 12 sheets is around $30. Not cheap, but worth the quality that you get. So when I paint, I like to make sure I am very certain with what I am going to paint so that I don't waste the paper. Which is why I like to draw on a lesser priced watercolor paper to practice and determine if my idea is even worth painting. I do most of my painting on weekends, since during the week I am busy running my business.
I start by drawing the idea on my black watercolor sketchbook to test things out. Am I even going to like the sketch and would it even be something that I would be inclined to paint? This also allows me to play around with ideas, because I rarely paint as I see it. I always try to put some unique spin on the painting that makes it my own.
Then when I feel satisfied that I have something that would work, I proceed to draw it on the watercolor paper and paint it. These images are my latest that I created yesterday to be painted this week. The first images is the test and the second the to be painted.