This way, there isn’t too much, or too little of their food items on hand. This is referred to as “inventory par levels”
After 20 years of working in restaurants, I adapted this to work in my home pantry.
This will help you save money. By shopping for basic staples, and keeping what you use on hand, you will have less waste. Once a month shopping also means less trips to the store, and less money out of pocket.