--- modules/aggregator.admin.inc	2010-06-26 15:55:47.000000000 -0400
+++ modules/aggregator.admin.inc	2010-10-03 18:11:33.000000000 -0400
@@ -61,7 +61,20 @@ function aggregator_view() {
  * @see aggregator_form_feed_submit()
  */
 function aggregator_form_feed($form, &$form_state, stdClass $feed = NULL) {
-  $period = drupal_map_assoc(array(900, 1800, 3600, 7200, 10800, 21600, 32400, 43200, 64800, 86400, 172800, 259200, 604800, 1209600, 2419200), 'format_interval');
+
+
+  // Discard items older than: Durations
+  $period = drupal_map_assoc(array(
+    // Less than one day.
+    900, 1800, 3600, 7200, 10800, 21600, 32400, 43200, 64800,
+    // 1-6 days.
+    86400, 2 * 86400, 3 * 86400, 4 * 86400, 5 * 86400, 6 * 86400,
+    // 1-3 weeks (7 days).
+    604800, 2 * 604800, 3 * 604800,
+    // 1-3,6,9 months (30 days).
+    2592000, 2 * 2592000, 3 * 2592000, 6 * 2592000, 9 * 2592000,
+    // 1 year (365 days).
+    31536000), 'format_interval');
   $period[AGGREGATOR_CLEAR_NEVER] = t('Never');
 
   $form['title'] = array('#type' => 'textfield',