I've only been at this game for about three years, and all my work has been done digitally. I've faced some criticism for not working traditionally (mostly from people who can't stand the idea of working digitally, go figure). I decided to buy a little 4.5"x5.5" sketchbook and some brush pens in an effort to see what all the fuss was about.
Initially, I was skeptical as to the usefulness of practicing in a medium that I don't produce my work with. All my skepticism was soon brushed aside as the ability to sketch whenever, wherever, and with no worry of lugging a tablet around was revealed.
I don't plan on ditching digital for my pencils and inks during final pieces. The ability to undo, cut objects out and move them around to tighten a composition, and the speed of creation can't be beat.
I do, however, intend to make notes, thumbnail, and generally document the early stages of my process with the sketchbook. It makes coming up with new work a lot easier for me. Sitting in front of the computer might not be the best way for me to work on new ideas. I found myself coming up with about twice as many pieces/hour with the sketchbook
The following pages are from my first day of trying out brush pens. Lots more thumbs were created, but I just wanted to give a taste of my new process - ballpoint pencils, brush pen inks, and, later, digital recreation.