What are the potential pitfalls of using single and double quotes in PHP code?

Using single and double quotes in PHP code can lead to confusion and errors, especially when trying to concatenate strings or include variables within quotes. To avoid these pitfalls, it is recommended to use single quotes for string literals that do not contain variables or special characters, and double quotes for strings that require variable interpolation or special characters. This will help maintain code readability and prevent unexpected behavior.

// Example of using single quotes for string literals and double quotes for variables
$name = 'John';
echo 'Hello, ' . $name . '!'; // Output: Hello, John!