The answer to 'when to replace GFCI outlet' is that you should replace a GFCI (ground fault circuit interrupter) outlet when it no longer functions properly, typically every 5-10 years or if it fails to trip when tested. GFCIs are designed to protect against electrical shock hazards, so it's important to keep them in good working condition.
Over time, the internal components of a GFCI can wear out or become damaged, causing it to fail to trip when a ground fault is detected. Additionally, GFCI outlets may become outdated or obsolete, and newer models may have improved safety features. If your GFCI outlet is not tripping when tested, making strange noises, or showing visible signs of damage, it's time to replace it to ensure your home's electrical safety.