Notebooks and To-Do Lists

I missed my bus to work this morning because I couldn't find my List Book. And then I realized - why does this silly little notebook matter so much to me? Are other people as dependent on notebooks as I am? I seriously cannot leave for work unless I have both of these in my purse/somewhere else easily accessible:

My two babies.

The one on the left is my food/exercise journal - I do write down everything that I eat/drink (except vitamins and water), as well as any exercise that I do. I also keep my Fritter Finder spreadsheet in it (weird combo, right? It just fits better in this one than the other one):

Fritter Finder (left) and food/exercise log (right).

The other one is my List Book. It has lists of phone numbers, to-do lists, grocery lists, menu plans, jotted down recipes, work-out plans, etc. in it. Seriously, I lose my marbles without this! It's without a doubt the most important of the two.

A sample page from my List Book.

I used to write lists of stuff I had to do or important numbers on scrap pieces of paper - which led to the problem of them either being unmanageable on a bulletin board, or lost in various bags and stacks. Notebooks are the key to my sanity.

Do you carry around a notebook or planner that you can't live without?