Global awareness of environmental issues has spurred interest in renewable energy sources, particularly solar energy, which emerges as a promising alternative. However, ensuring efficiency throughout the lifespan of photovoltaic (PV) plants, which can extend up to 25 years, requires high-quality installations, regular maintenance, and thorough inspections. This study proposes implementing an integrated evaluation system alongside a performance monitoring tool to enhance the management of Operation and Maintenance (O&M) services for PV plants. This study assesses the performance of key performance indicators (KPIs) for a 1 MWp PV plant to evaluate the effectiveness of O&M services. Regular assessments of these services can identify areas for improvement within the maintenance team, such as optimizing procedures contributing to the continuous enhancement of the photovoltaic system. Effective O&M practices are critical to ensure optimal performance of existing installations and minimize downtime due to failures. Frequently, O&M services are outsourced and formalized through contracts, playing a pivotal role in defining responsibilities. In this context, KPIs are valuable tools to support proposals for contractual adjustments, providing a solid foundation for discussions and modifications.