In what situations is it advisable to use the == operator instead of the = operator in PHP conditional statements?

It is advisable to use the == operator instead of the = operator in PHP conditional statements when you want to compare two values for equality. The == operator checks if the values on both sides are equal, while the = operator is used for assignment. Using the wrong operator can lead to unintended consequences, such as unintentionally assigning a value instead of comparing it.

// Incorrect usage of the = operator
$var = 10;

// Correct usage of the == operator
if ($var == 10) {
    echo "The value of var is 10.";
}