FUD.php

<?php

$properties = array(
    'y' => 'years', 
    'm' => 'years', 
    'd' => 'years', 
    'h' => 'years', 
    'i' => 'years', 
    's' => 'years',
);
$formatted = '';

foreach ($properties as $key => $label) {
    if (!$value = $dateDiff->$property) continue;
    $formatted = "$value $label";
    break;
}