I began keeping loose-leaf notebooks some thirty years ago when I attended classes and workshops. In the beginning they included not much more than some exemplars and practice lettering sheets. When I found I was becoming a pack rat, I realized that it made more sense to place the exemplars in clear sheet protectors and keep only those bits and pieces that I knew I might revisit when the creative muses were on vacation.
Later, as I added classes in life drawing, watercolor and pastel, I switched to spiral bound sketchbooks. I still use notebooks for exemplars, but now I use the sketchbooks to take notes, cut and paste small examples from workshops, and to experiment with design, color and tools. They have become an invaluable reference.