Service products are typically intangible, perishable, and heterogeneous, and can be performed, delivered, or consumed by customers. To test and validate sales assumptions and hypotheses for service products, you need to consider the quality and consistency of your product. This includes measuring and improving service quality with service quality dimensions such as reliability, responsiveness, assurance, empathy, and tangibles. You also need to determine the optimal price point and value proposition for your service product. This includes accounting for the perceived value, value-added services, and value-based pricing. Lastly, you need to build a strong relationship and loyalty with your customers by fostering trust, communication, and engagement. You can test and validate these factors with service audits, quality control surveys, value proposition canvas, customer lifetime value analysis, return on investment calculations, customer relationship management initiatives, customer retention strategies, and net promoter score assessments.