If your firm makes parts for a customer, offer to tell them the flaws with their product’s design that your engineers have noted, what aspects of the product that are engineered to be excessively costly, offer suggestions for cheaper materials or suggestions for better product design, ideas for better packaging, less costly freight options and any other attribute that can be improved. You will make yourself more valuable to your customer and most likely ensure your continued business by going beyond the requirements of your purchase order. You offer the cost reductions and tell the customer he is under no obligation to take the suggestions. It is part of your service. Tell him you know if you make him more than happy, he is less likely to leave or go elsewhere for service.