Drawing in graphite in one of my sketchbooks. When I was younger I used to fill up sketchbooks very fast. But now they last for years. Obviously because my time gets filled up with other things but also I realize that I have several sketchbooks going at the same time. They all have different types of paper and are all of different sizes. I have one small note book sized Moleskine , a larger 8X11 Molskine , another 8x11 book with really thick, hot pressed paper which is good for inking and several Aquabee books that has thick cold pressed paper in it plus a watercolor sketch book.
I need to go back and revisit some of those sketches and feed off of them for new drawings. I think that's a good use for sketchbooks . Originally I just used them for "practice" . Seems like I'm always practicing .