A little trick that I learned about replacing expendables was to leave the wrapper/can/bottle/whatever somewhere visible until it's replaced. For example, I filled up the washer fluid in the car the other day during the ice storm, and used up the bottle from the back of the truck. I put the empty plastic bottle on the floor on the passenger side of the truck, rather than throwing it out at the rest stop trash can. When I got home, I grabbed a fresh one from the garage, and put it back in the truck. It's hard to forget, because if my wife gets in the truck, the first thing she'll notice is the empty washer fluid bottle at her feet!

FAK's are notorious for having stuff used and not replaced. To a certain extent, you expect that. I know we have a checklist on all of ours, and a little golf pencil in the kit. If you use something, put a tick mark next to it. Of course, someone has to check the list on a regular schedule. (The missing link!)

At work, I know that we have a professional service that comes and replaces fire extinguishers with recharged ones, puts new batteries in the emergency lighting, and services the FAK's. I think those FAK's are designed with a significant excess supply of commonly used items, so I think the annual check is all they do, unless something bad happens around the place during the year.