Just a suggestion. It does not necessarily have to apply to any specific business. But then again. Why not? Maybe this will help you to appreciate the perspicacity of always having enough in stock to fall back on in times of need. Take the laundry business for instance. It would not matter whether it is a smallish corner retail operation that you are used to calling on yourself, or whether it is one of those larger businesses that are catering for heavy restaurant and industrial use. In these lines, there are a lot of uniforms to be washed and dried.
And that is good business for the laundry operator. Such a business will always have its clients. The tap will never run dry. But then again. It could. Because whatever should happen when the business abruptly runs out of its requisite laundromat parts and components. The machines having come to a standstill, the business has no alternative but to halt its operations. And when that happens, substantial revenue gets lost. It could get worse. Hard pressed (just like you) and discerning customers do not have the time of day to hang around waiting for you to fix those machines already.
And then there is also the matter of having a reliable mechanic to fix the machines. Ask any laundromat owner, it should be usual for parts and components to wear down. The business is non-stop and there is the usual wear and tear. So it all goes to show that a good backup in inventory goods is necessary. The same goes for other necessities like washing powders and detergents, brushes, hangers and the like. And having a reliable and qualified mechanic to call on at a moment’s notice.