In the practice of most manufacturing and service companies, the best results are achieved not by choosing a single model, but by a well-designed combination of them https://www.novacura.com/maintenance-and-field-service/. Reactive maintenance is difficult to completely eliminate, but its share should be minimal and considered the exception rather than the norm. Experience shows that preventive maintenance forms the foundation of sustainable operations: scheduled inspections, planned component replacements, and standardized checklists can significantly reduce the number of accidents and equipment downtime. The most mature organizations are gradually moving toward predictive maintenance. Using sensor data, failure history, and analytics helps identify potential problems early and schedule engineer visits when they are truly needed. This approach positively impacts not only equipment reliability but also the workload of the service team, making their work more predictable and efficient. As for KPIs, combined metrics have proven effective in practice. For field engineers, these typically include average response time, equipment repair time, percentage of work completed on the first visit, and compliance with safety regulations. For the service department as a whole, it is important to track equipment availability, unplanned downtime levels, customer satisfaction, and actual service costs compared to planned costs.