Check if there is 24 hours gone since a Woocommerce order is made

Here is the way to check if there is more (or less) than 24 hours passed since an order has been created, using WC_DateTime and DateTime methods on Order created date time:

$order = wc_get_order($order_id); // Get an instance of the WC_Order Object

$date_created_dt = $order->get_date_created(); // Get order date created WC_DateTime Object
$timezone        = $date_created_dt->getTimezone(); // Get the timezone
$date_created_ts = $date_created_dt->getTimestamp(); // Get the timestamp in seconds

$now_dt = new WC_DateTime(); // Get current WC_DateTime object instance
$now_dt->setTimezone( $timezone ); // Set the same time zone
$now_ts = $now_dt->getTimestamp(); // Get the current timestamp in seconds

$twenty_four_hours = 24 * 60 * 60; // 24hours in seconds

$diff_in_seconds = $now_ts - $date_created_ts; // Get the difference (in seconds)

// Output
if ( $diff_in_seconds < $twenty_four_hours ) {
    echo '<p>Order created LESS than 24 hours ago</p>';
} elseif ( $diff_in_seconds = $twenty_four_hours ) {
    echo '<p>Order created 24 hours ago</p>';
} else {
    echo '<p>Order created MORE than 24 hours ago</p>';
}