Of all the things that will kill your business, the one that will kill it the quickest is misunderstanding capital risk.
This is less of a problem later on in a company's lifetime, and both more obvious and less difficult for newly founded companies: the point where failing to appreciate this is most likely to do you harm is in the transition from your first major customer, to obtaining enough customers to make you a profitable business.
It is less of an issue - though still crucial - for service-based business. It is life and death for businesses that make and sell physical goods.
Capital, obviously enough, is the cash that you have in hand - which is the business' ability to do things. If you are a goods-based business, then the first and most important of those things is
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Buy components, to make more product
Very obviously, this is a feedback loop: the less cash you have in hand, the fewer components you can afford to buy, the fewer products you have available to sell, so the less cash you have. The more cash in hand, the more products you can build, the more products you can sell, the more cash you have...