What are the potential pitfalls of using numeric values within PHP functions and expressions?

Using numeric values directly within PHP functions and expressions can lead to code that is hard to read, maintain, and debug. It is best practice to assign numeric values to meaningful variables with descriptive names to improve code readability and maintainability. This also allows for easier modification of values in the future without having to search and replace throughout the code.

// Bad practice: using numeric values directly
$total = 100 + 20;
$discountedPrice = $total * 0.8;

// Good practice: assigning numeric values to variables
$basePrice = 100;
$discount = 0.2;
$total = $basePrice + 20;
$discountedPrice = $total * (1 - $discount);