Post is older than: Adding this first block of code to your functions.php will allow you to check the age of a post to see if it is older than a set number of days. Great if you want to display some some information related to the post after set number of days or even stop displaying the post altogether.

function.php

   function is_old_post($days = 5) {
       $days = (int) $days;
       $offset = $days*60*60*24;
       if ( get_post_time() < date('U') - $offset )
            return true;
       return false;
    }

loop.php

    if ( is_old_post(10) ) {
      // do something if the post is old
      } else {
      // do something if the post is not old
    }