Self-employed people need to be highly pro-active.
Just like an employee, a self-employed person will need to develop other cashflow assets as one-day physical and mental deterioration are likely to reduce the amount of time available to generate cash inflow.
When a self-employed person begins to employ people and build a team which supports them in the delivery of their services, the transformation to a business begins.
Over time, the self-employed person may find others who can keep the customers happy while they go on holidays, and return to find that the cash inflow has continued to flow.
When this happens, the cashflow source has moved from self-employment to business.