One of my favorite books is this teen romance from another era called Dinosaur and Deathtrap. It's out of print now and I recently bought used copies when gripped by an abject fear that my hypothetical children might not have the chance to read it. In this book, the girl (Bethany) and her dad have a system where they buy two of everyday household products, and whenever one runs out they pull out the other and immediately write it on the grocery list on the fridge. Old school FlyLady! Anyway, I thought this was brilliant and as soon I came into possession of my own need of household products and my own refrigerator, implemented this system. (My sister once pointed out that there is no functional difference between this system and simply buying things when I run out of them. No comment.) I have a terrific magnetic pad that goes on my fridge and have continued to brainstorm ways to get a pencil up there, other than the obvious buying a new magnetic pad with a pencil attached. I can't do this because I have occasionally taken my system to an extreme and bought things in multiples greater than two and this may or may not be applicable to the terrific magnetic pads I bought, which I may or may not have bought 18 of at Target. Magnetic pencil holder!!
$9.95 at Tiny Living (My, that's a lot of neuroses in one post...)