How do I know if a GFCI needs to be replaced?

As a homeowner concerned about electrical safety, I'm wondering how I can determine if my Ground Fault Circuit Interrupter (GFCI) outlet needs to be replaced. Are there any visible signs of wear or malfunction that I should be aware of? Do GFCI outlets have a typical lifespan, or do they require replacement based on usage? What are the potential consequences of a faulty GFCI outlet, and how can I safely test its functionality? Is it recommended to replace GFCIs with newer models as technology advances, or can older ones be relied upon for continued protection? Understanding these factors will help me ensure my home's electrical system remains SAFE and reliable.