What are some common mistakes to avoid when using conditional statements in PHP?

One common mistake to avoid when using conditional statements in PHP is forgetting to use double equals `==` for comparison instead of a single equals `=` for assignment. This can lead to unintended behavior and errors in your code. Always double-check your conditional statements to ensure you are comparing values correctly.

// Incorrect comparison using single equals
$number = 5;
if($number = 5) {
    echo "Number is 5";
}

// Correct comparison using double equals
$number = 5;
if($number == 5) {
    echo "Number is 5";
}