What potential pitfalls can arise from duplicating modules in PHP development?

Duplicating modules in PHP development can lead to code redundancy, making maintenance and updates more complicated. To avoid this issue, you can create reusable functions or classes that can be called multiple times throughout your codebase.

// Example of creating a reusable function to avoid duplicating modules
function calculateArea($length, $width) {
    return $length * $width;
}

// Example of calling the function to calculate area
$area1 = calculateArea(5, 10);
$area2 = calculateArea(3, 7);

echo "Area 1: $area1\n";
echo "Area 2: $area2\n";