I have a few friends who are mechanical and electrical engineers and they always use a notebook. Apparently its so that they can document their work and though

I have a few friends who are mechanical and electrical engineers and they always use a notebook. Apparently its so that they can document their work and thought process continuously, just incase they ever need to justify why they did something. I've started to do it myself because it seemed like a good idea. It definitely beats having random pieces of copier paper that are piled up in a mess all over my desk.