What are the best practices for maintaining and managing MEP systems in existing buildings? I'm looking for advice on ensuring the longevity and efficiency of these systems. Specifically, I'm interested in strategies for regular maintenance schedules, the role of technology in monitoring system performance, and ways to address common issues before they become major problems. Any insights on integrating sustainable practices and energy-saving measures into the maintenance routine would also be appreciated. How do you balance the need for regular upkeep with minimizing disruption to building occupants?