I have been building a library of checklists since the first year I entered the building industry. I found that I couldn't retain everything I was learning, as my education was continuous and diversified. I began to write down as much of the lessons learned as I went along.
Volume one of my library was a spiral notebook, which I still have, where I would write down rules of thumb, budget values, etc. Later, I began using a three-ring binder to store my checklists because it made good business sense to not try and memorize all of it. It was easier to collect, retain, and inventory the tasks this way.