Here is an example on how to check to difference bewteen two dates in using PHP.
<? $now = time(); $week = time()+60*60*24*7; $diff = $week-$now; echo $diff/(60*60*24)." days "; // 7 Days echo $diff/(60*60)." hours "; // 168 hours echo $diff/(60)." minutes "; // 10080 minutes ?>