How old can fire sprinkler heads be before using?

Fire sprinkler heads should ideally be replaced if they are over 50 years old, as their effectiveness and reliability can diminish over time. Regular inspections and testing are essential to ensure they function properly. Additionally, any sprinkler heads that show signs of corrosion, physical damage, or have been exposed to extreme temperatures may need to be replaced regardless of their age. Always follow local regulations and manufacturer guidelines for specific replacement recommendations.