for over 20 years, I had grown accustomed to seeing the storeroom shelves stocked with at least two weeks' supply of goods. The rule was, "you NEVER run out of anything", no matter what lengths you must go get product. For non-perishables, that meant having a minimum of twice what you thought you would use on hand.
Some of that has carried over to my buying habits today, and I usually have a backup for everything I use - I buy an item when I get down to only one on the shelf, not when my one item is almost empty.
This will not necessarily work for everything for extended periods, but it will take care of a whole lot of it.
To me, it's the same as filling the gas tank when it gets down to near half, rather than waiting until I'm empty, not to mention the full jerry cans in the shop.