What’s more annoying that having someone leave an empty roll of toilet paper? Having that happen, and having no more in the house.
It’s okay to run out of some things. Paper towels? Use a cloth. Juice? Drink water. However, it is very inconvenient to run out of other things: printer ink, laundry soap, deodorant; when you need them, you need them now.
The amount that you need to keep as a back-up depends on your family situation and space available. Those warehouse stores strongly encourage us to keep a year’s supply, but if you live in a 500 square-foot apartment, 60 rolls of toilet paper may take up half your closet. The half-gallon of mayonnaise may go bad before you can finish it.
Find your balance. Decide what is critical to maintain extra supplies of. Train the people in your home to report- or better yet to write on the grocery list- when they are using the last of the supply. And remember, if you have minimal storage, you can consider the grocery store your back-up warehouse.