define('TIME', 24); // 24 hours 
define('YOUR_ALLOWED', 5); // 5 a day 

            $sql = 'SELECT count(test_topic_id) as test_count 
                FROM ' . TEST_TABLE . '
                WHERE test_time > ' . (time() - 3600 * TIME) . '
                AND test_poster_id = ' . $user->data['user_id']; 
            $row = $db->sql_fetchrow($db->sql_query($sql));
            if ($row['test_count'] >= YOUR_ALLOWED)
            {
                return true; // Daily Limit. We've made all we're allowed.
            }
        }
        
        return false; // We haven't hit our limit. ! No limits on me! hehe