Concentration is a hidden liability that never appears on any statement. Once a single customer passes roughly 40 per cent of revenue, they own your pricing, your calendar and your risk. You will notice you have stopped being able to say no - to late payment, to scope that keeps growing, to work at short notice. At that point you are effectively a department of their company, carrying all the exposure of a business owner and none of the security of an employee.

The remedy is not more hustle, it is a protected allocation. Fix a small block of time - four hours a week is enough - for pipeline work, and defend it while the big client is still paying. The worst possible moment to go looking for customers is the moment you need one, because desperation shows in your pricing and your patience.

Spend that block in the right order. First, two or three more customers in the same segment, because the offer is already proven and the objections are already known. Second, one written case study from the big client's work, which does the selling for you. Third, one relationship in a different sector, so that a downturn in one industry does not take your whole year.