This is where most building owners fail. NFPA 72 requires rigorous schedules:
Added heavily in the 2010 and 2013 editions. This chapter governs "in-building mass notification" used for non-fire emergencies (terrorism, severe weather).
A system that isn't maintained is a liability. Chapter 14 provides strict schedules:
NFPA 72 is organized into distinct chapters, each addressing a specific aspect of the lifecycle of a system.