To measure and sustain the benefits of the 5S principles, you need to establish a system of monitoring and control that ensures the adherence and improvement of your 5S project. To do this, define and track key performance indicators (KPIs) such as cycle time, defect rate, inventory level, customer satisfaction, and employee engagement. Additionally, conduct regular and random inspections of your work area using tools such as checklists, scoring systems, and charts. Collect feedback from team members, managers, customers, and suppliers on the strengths and weaknesses of your 5S project by using surveys, interviews, focus groups, and suggestion boxes. Acknowledge and reward the efforts and achievements of your team members with certificates, badges, bonuses, or celebrations. Finally, continuously look for ways to enhance and refine your 5S project based on the data and feedback you collect by using brainstorming, benchmarking, or best practices.