How can PHP developers ensure that date formatting functions are used correctly to avoid errors like those encountered in the forum thread?

To ensure that date formatting functions are used correctly and avoid errors, PHP developers should always refer to the official PHP documentation for the correct format specifiers. Additionally, it's important to validate input dates before formatting them to prevent unexpected results. Using functions like `strtotime()` or `DateTime::createFromFormat()` can help ensure that the input date is in a valid format before applying the desired date formatting.

$input_date = "2022-05-15";

// Validate input date
if ($timestamp = strtotime($input_date)) {
    $formatted_date = date("Y-m-d", $timestamp);
    echo $formatted_date;
} else {
    echo "Invalid input date!";
}