Soap. Simple, right? You use antibacterial squirt soap at the sink, have a bar of bath soap at the tubs, and gallons of laundry soap near your washing machine. But do you have enough?
Take a look at your receipts for last year. How often did you buy these things? Did you have enough? Did you have spur-of-the-moment trips to the store because you ran out of Cheer in the middle of doing laundry?
Did you know that in a pinch, you can use bar soap in your hair, and do you really need the convenience of squirt soap when bar soap will work just as well? How about using that same bar soap to do a load of wash (shavings)!
Do an inventory check. Then do a reality check. How much do you REALLY need per week. Per month. Per year.
Then make sure every time you buy one soap, you buy an extra or two for your storage plans.