What with work, weather, and every day use, a hard hat can get old before its time. You'll know when it is time to get a new hard hat when:
• Cracks appear in the shell.
• Shiny surface appears dull or chalky.
• Shell becomes brittle.
While you're at it, check your suspension. You'll know when you need a fresh one if:
• The suspensions become brittle
• One or more of the mounts break off
• The suspension will no longer hold securely to the head
• The cradling straps break or become worn
It is generally a good idea to inspect your hard hat before and after each use. Although there is no set service life for hard hats, manufacturers recommend replacement after no more than 5 years.