I have recently decided a dry erase board would be a good addition to the shop, so I picked up a 24x30 one at Staples yesterday. Right now it just has some shop projects written on it that I want to get done, but I see it being useful for shopping lists, writing measurements, checking math, rough sketching, etc.
Prior to that, I would would write things on a piece of paper or a piece of wood, but the inevitable result is losing them or using them for another purpose.
I am not sure how other people handle things like this, but for me this seems like a really good way to quickly notate and idea or jot down something I need before I forget it.
Robby