How important is it to pay attention to casing when programming in PHP, and what impact can it have on the code?

It is crucial to pay attention to casing in PHP as it is a case-sensitive language. Failing to use the correct casing can result in errors such as undefined variable or function names. To avoid these issues, always ensure that you use consistent casing for variables, functions, and class names throughout your code.

// Incorrect casing
$myVariable = "Hello World";
echo $myvariable; // This will result in an error

// Correct casing
$myVariable = "Hello World";
echo $myVariable; // This will output "Hello World"