diff --git a/advagg.install b/advagg.install
index ebda908..454dcdf 100644
--- a/advagg.install
+++ b/advagg.install
@@ -487,8 +487,19 @@ function advagg_schema() {
         'not null' => TRUE,
         'default' => 0,
       ),
+      'timestamp' => array(
+        'description' => 'Last used timestamp of the bundle.',
+        'type' => 'int',
+        'not null' => TRUE,
+        'default' => 0,
+      ),
     ),
-    'primary key' => array('bundle_md5', 'filename_md5'),
+    'indexes' => array(
+      'root'        => array('root'),
+      'timestamp'   => array('timestamp'),
+      'counter'     => array('counter'),
+    ),
+    'primary key'   => array('bundle_md5', 'filename_md5'),
 
   );
 
@@ -625,3 +636,62 @@ function advagg_update_6107() {
 
   return $ret;
 }
+
+/**
+ * Update 6108 - Add new field & add indexes to advagg_bundles table.
+ */
+function advagg_update_6108() {
+  $ret = array();
+
+  // Add in timestamp column.
+  db_add_field($ret, 'advagg_bundles', 'timestamp', array(
+        'description' => 'Last used timestamp of the bundle.',
+        'type' => 'int',
+        'not null' => TRUE,
+        'default' => 0,
+      ));
+
+  // Add in indexes.
+ db_add_index($ret, 'advagg_bundles', 'root', array('root'));
+ db_add_index($ret, 'advagg_bundles', 'timestamp', array('timestamp'));
+ db_add_index($ret, 'advagg_bundles', 'counter', array('counter'));
+
+  // Populate timestamps.
+  list($css_path, $js_path) = advagg_get_root_files_dir();
+  $results = db_query("
+    SELECT
+      ab.bundle_md5,
+      ab.counter,
+      af.filetype
+    FROM {advagg_bundles} AS ab
+    INNER JOIN {advagg_files} AS af USING ( filename_md5 )
+    GROUP BY bundle_md5");
+  while ($row = db_fetch_array($results)) {
+    $filename = advagg_build_filename($row['filetype'], $row['bundle_md5'], $row['counter']);
+    if ($row['filetype'] == 'css') {
+      $file_type_path = $css_path;
+    }
+    else {
+      $file_type_path = $js_path;
+    }
+    $filepath = $file_type_path .'/'. $filename;
+
+    $data = cache_get($filepath, 'cache_advagg');
+    if (!empty($data->data)) {
+      // Set timestamp if it exists in the cache.
+      db_query("UPDATE {advagg_bundles} SET timestamp = %d WHERE bundle_md5 = '%s'", $data->data, $row['bundle_md5']);
+      $ret[] = array('success' => TRUE, 'query' => 'Timestamp added for: ' . $filename . '.');
+    }
+    else {
+      $ret[] = array('success' => TRUE, 'query' => 'No timestamp found for: ' . $filename . '.');
+    }
+  }
+
+  $cache_tables = advagg_flush_caches();
+  foreach ($cache_tables as $table) {
+    cache_clear_all('*', $table, TRUE);
+  }
+  $ret[] = array('success' => TRUE, 'query' => 'AdvAgg Caches Flushed.');
+
+  return $ret;
+}
diff --git a/advagg.missing.inc b/advagg.missing.inc
index f4cb50b..5b89fcb 100644
--- a/advagg.missing.inc
+++ b/advagg.missing.inc
@@ -50,33 +50,12 @@ function advagg_missing_regenerate() {
   $filename = array_pop($arg);
   $filename = array_shift(explode('?', $filename));
 
-  // Verify requested filename has the correct pattern.
-  if (preg_match('/^(j|cs)s_[0-9a-f]{32}_\d+\.(j|cs)s$/', $filename) == FALSE) {
-    return t('Wrong Pattern.');
-  }
-
-  // Get type
-  $type = substr($filename, 0, strpos($filename, '_'));
-
-  // Get extension
-  $ext = substr($filename, strpos($filename, '.', 37)+1);
-
-  // Make sure extension is the same as the type.
-  if ($ext != $type) {
-    return t('Type does not match extension.');
-  }
-
-  // Extract info from wanted filename.
-  if ($type == 'css') {
-    $md5 = substr($filename, 4, 32);
-    $counter = substr($filename, 37, strpos($filename, '.', 38)-37);
-  }
-  elseif ($type == 'js') {
-    $md5 = substr($filename, 3, 32);
-    $counter = substr($filename, 36, strpos($filename, '.', 37)-36);
+  $data = advagg_get_bundle_from_filename($filename);
+  if (is_array($data)) {
+    list($type, $md5, $counter) = $data;
   }
   else {
-    return t('Wrong file type.');
+    return $data;
   }
 
   $_GET['redirect_counter'] = isset($_GET['redirect_counter']) ? intval($_GET['redirect_counter']) : 0;
diff --git a/advagg.module b/advagg.module
index c9eebcb..fca3353 100644
--- a/advagg.module
+++ b/advagg.module
@@ -519,9 +519,10 @@ function advagg_get_filename($files, $filetype, $counter = FALSE, $bundle_md5 =
       advagg_insert_bundle_db($files, $filetype, $bundle_md5, TRUE);
     }
     // If bundle should be root and is not, then make it root.
-    $root = db_result(db_query("SELECT root FROM {advagg_bundles} WHERE bundle_md5 = '%s'", $bundle_md5));
-    if ($root === 0) {
-      db_query("UPDATE {advagg_bundles} SET root = '1' WHERE bundle_md5 = '%s'", $bundle_md5);
+    // Refresh timestamp if older then 12 hours.
+    $row = db_fetch_array(db_query("SELECT root, timestamp FROM {advagg_bundles} WHERE bundle_md5 = '%s'", $bundle_md5));
+    if ($row['root'] === 0 || time() - $row['timestamp'] > variable_get('advagg_file_last_used_interval', ADVAGG_FILE_LAST_USED_INTERVAL)) {
+      db_query("UPDATE {advagg_bundles} SET root = '1', timestamp = %d WHERE bundle_md5 = '%s'", time(), $bundle_md5);
     }
   }
 
@@ -660,7 +661,7 @@ function advagg_find_existing_bundle(&$files, &$bundle_md5) {
   sort($temp_files);
   $cached_data_key = 'advagg_existing_' . md5(implode('', $temp_files));
 
-  // Try cache first; cache table is cache_advagg_bundle_reuse.
+  // Try cache first; cache table is cache_advagg_bundle_reuse. string is debug name.
   $cached_data = advagg_cached_bundle_get($cached_data_key, 'advagg_find_existing_bundle');
   if (!empty($cached_data)) {
     $files = $cached_data[0]['files'];
@@ -675,7 +676,7 @@ function advagg_find_existing_bundle(&$files, &$bundle_md5) {
   $args = array();
   $counter = 0;
   foreach ($files as $filename) {
-    // use char for table aliases.
+    // Use alpha for table aliases; numerics do not work.
     $key = strtr($counter, '01234567890', 'abcdefghij');
 
     $joins[$key] = "\nINNER JOIN {advagg_bundles} AS $key USING(bundle_md5)\n";
@@ -745,7 +746,7 @@ function advagg_insert_bundle_db($files, $filetype, $bundle_md5, $root) {
     }
 
     // Create the entries in the advagg_bundles table.
-    db_query("INSERT INTO {advagg_bundles} (bundle_md5, filename_md5, counter, porder, root) VALUES ('%s', '%s', '%d', '%d', '%d')", $bundle_md5, $filename_md5, 0, $order, $root);
+    db_query("INSERT INTO {advagg_bundles} (bundle_md5, filename_md5, counter, porder, root) VALUES ('%s', '%s', '%d', '%d', '%d')", $bundle_md5, $filename_md5, 0, $order, $root, time());
   }
 }
 
@@ -1018,7 +1019,7 @@ function advagg_checksum($filename) {
 }
 
 /**
- * See if this bundle has been built yet.
+ * See if this bundle has been built.
  *
  * @param $filepath
  *   filename
@@ -1026,11 +1027,20 @@ function advagg_checksum($filename) {
  *   Boolean indicating if the bundle already exists.
  */
 function advagg_bundle_built($filepath) {
+  $data = advagg_get_bundle_from_filename(basename($filepath));
+  if (is_array($data)) {
+    list($type, $md5, $counter) = $data;
+  }
+  else {
+    return FALSE;
+  }
+
   $data = cache_get($filepath, 'cache_advagg');
-  if (!empty($data->data)) {
+  if (isset($data->data)) {
     // Refresh timestamp if older then 12 hours.
     if (time() - $data->data > variable_get('advagg_file_last_used_interval', ADVAGG_FILE_LAST_USED_INTERVAL)) {
       cache_set($filepath, time(), 'cache_advagg', CACHE_PERMANENT);
+      db_query("UPDATE {advagg_bundles} SET timestamp = %d WHERE bundle_md5 = '%s'", time(), $md5);
     }
     return TRUE;
   }
@@ -1047,9 +1057,43 @@ function advagg_bundle_built($filepath) {
   }
   // File existed on disk; place in cache.
   cache_set($filepath, time(), 'cache_advagg', CACHE_PERMANENT);
+  db_query("UPDATE {advagg_bundles} SET timestamp = %d WHERE bundle_md5 = '%s'", time(), $md5);
   return TRUE;
 }
 
+function advagg_get_bundle_from_filename($filename) {
+  // Verify requested filename has the correct pattern.
+  if (preg_match('/^(j|cs)s_[0-9a-f]{32}_\d+\.(j|cs)s$/', $filename) == FALSE) {
+    return t('Wrong Pattern.');
+  }
+
+  // Get type
+  $type = substr($filename, 0, strpos($filename, '_'));
+
+  // Get extension
+  $ext = substr($filename, strpos($filename, '.', 37)+1);
+
+  // Make sure extension is the same as the type.
+  if ($ext != $type) {
+    return t('Type does not match extension.');
+  }
+
+  // Extract info from wanted filename.
+  if ($type == 'css') {
+    $md5 = substr($filename, 4, 32);
+    $counter = substr($filename, 37, strpos($filename, '.', 38)-37);
+  }
+  elseif ($type == 'js') {
+    $md5 = substr($filename, 3, 32);
+    $counter = substr($filename, 36, strpos($filename, '.', 37)-36);
+  }
+  else {
+    return t('Wrong file type.');
+  }
+
+  return array($type, $md5, $counter);
+}
+
 /**
  * Implementation of hook_flush_caches().
  */
@@ -1106,7 +1150,7 @@ function advagg_flush_caches() {
 
   foreach ($bundles as $bundle_md5) {
     // Increment Counter
-    db_query("UPDATE {advagg_bundles} SET counter = counter + 1 WHERE bundle_md5 = '%s'", $bundle_md5);
+    db_query("UPDATE {advagg_bundles} SET counter = counter + 1, timestamp = %d WHERE bundle_md5 = '%s'", time(), $bundle_md5);
 
     if (variable_get('advagg_rebuild_on_flush', ADVAGG_REBUILD_ON_FLUSH)) {
       // Rebuild bundles
@@ -1229,7 +1273,7 @@ function advagg_get_file_data($filename_md5) {
 }
 
 /**
- * Get data about a file.
+ * Set data about a file.
  *
  * @param $filename_md5
  *   md5 of filename.
@@ -1827,6 +1871,10 @@ function advagg_css_js_file_builder($type, $files, $counter = '', $force = FALSE
     // Try cache first; cache table is cache_advagg_bundle_reuse.
     $cached_data = advagg_cached_bundle_get($cached_data_key, 'file_builder_cache_object');
     if (!empty($cached_data)) {
+      foreach ($cached_data as $filepath => $values) {
+        // Ping cache.
+        advagg_bundle_built($filepath);
+      }
       return $cached_data;
     }
   }
diff --git a/advagg_bundler/advagg_bundler.module b/advagg_bundler/advagg_bundler.module
index 95204ed..252501b 100644
--- a/advagg_bundler/advagg_bundler.module
+++ b/advagg_bundler/advagg_bundler.module
@@ -19,6 +19,12 @@ define('ADVAGG_BUNDLER_MAX_CSS', 4);
 define('ADVAGG_BUNDLER_MAX_JS', 4);
 
 /**
+ * Default value of the last used time before the bundle is considered outdated.
+ * 2 weeks in seconds.
+ */
+define('ADVAGG_BUNDLER_OUTDATED', 1209600);
+
+/**
  * Implementation of hook_menu
  */
 function advagg_bundler_menu() {
@@ -153,8 +159,9 @@ function advagg_bundler_analysis($filename = '') {
       FROM {advagg_bundles} AS ab
       INNER JOIN {advagg_files} AS af USING ( filename_md5 )
       WHERE ab.root = 1
+      AND timestamp > %d
       GROUP BY ( af.filename )
-    ");
+    ", time() - variable_get('advagg_bundler_outdated', ADVAGG_BUNDLER_OUTDATED));
 
     $counter = array();
     while ($row = db_fetch_array($result)) {