That’s about as old skool as you can get unless you want to go all the way back to the BTM bombe.
I’m retired now, but up till the last day I worked I kept those cards in the pocket of my suit jacket to take notes.
I also wrote my daily and weekly schedules on them.
Sort of like a vest pocket Franklin Planner.
What people do now on their phones and Blackberries I did on 80 column cards.
When they stopped using cards, I went to a print shop and ordered several reams of cut card stock.