This client cost me $150K right before Christmas. Here’s the business lesson. Restaurant client needed cleaning, painting, minor construction. Did the site visit, started working. First invoice - payment missed. “The investors are sending the money.” Second invoice - payment missed again. Same excuse. But I kept working because other contractors were there, I thought it was legitimate. Then one day - restaurant closed. Food suppliers outside. All unpaid. I lost $150K. Client red flags I missed: