A healthy cashflow means that you have multiple profitable financial streams coming in at once. A business with a healthy income is earning more money and has more fallback solutions if major clients stop payments, or a service falls out of favour with its customer base. A cashflow in poor health means that one good year's results can be completely wiped out by the business suddenly losing a lot of income in the next, with no other financial safety nets to keep payments coming in and new clients arriving.