I use beersmith to design my recipes. I print out the brew sheet and BruNwater adjustments for brewday. I write all notes on the back of the brewsheet. After brew day is over it goes into a 3 ring binder. If I enter it into competition, the scoresheets get placed in the sleeve with the recipe.
I learned the hard way that if you want to make good beer and really understand what you are doing, you need great notes. Early on, I made some great brews. Then started delving into new techniques and water adjustments, etc. Eventually all my beer was lackluster and because I made so many changes without writing it down, I had no clue where I strayed. Fast forward, I now take detailed notes on anything relatively important. I know some brewers are fine with being a bit lackadaisical on their practices, but that is just not for me. Or anyone who is a slight perfectionist.