We need to plan because, like a household budget, the income for your business budget must be estimated for the upcoming months in order to determine if you eill have enough cash to pay for all of your planned and unplanned expenses.
If you plan in advance that your business income will be low in the first few months of of operations, which is normal in a new business, then you can make plans for the additional cash required to keep the doors open during this slow time. You will also be able to modify your cash outflows to only the ones that are necessary and not take on additional expenses until the business income grows and you can comfortable handle these expenses.
Your business must make a profit eventually in order to stay in business. You should expect to incur losses for the first few months to a year in a new business startup. By budgeting and planning the cash you are short, you will not be in for any surprises and you will know in advance how much cash you as the owner may need to put into the business.
In short, preparing a cash flow informs your decisions and is a part of your financial management. You must manage the finances of your business by filing all receipts to ensure accurate budgeting and proper records for tax purposes. Many business owners hire a bookkeeper or accountant to complete their cash flow and other financial statements. Whether you do this or not, you still need to understand your cash flows and financial statements and why these are a key part of your business planning.