What common mistake do developers make with Class-based components, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Class-based components, why does the mistake cause problems, and what is the safer approach? One recurring problem with class-based components is applying it without understanding the boundary it protects. Creating a component for a fragment that has no reuse value and then making the component interface more complicated than the original markup. In addition, Class-based components can hold PHP-side data or presentation logic that belongs with a reusable UI element. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.