Index: core/install/step_templates/sys_config.tpl
===================================================================
--- core/install/step_templates/sys_config.tpl
+++ core/install/step_templates/sys_config.tpl
@@ -8,6 +8,7 @@
 		'ApplicationClass' => Array ('type' => 'text', 'title' => 'Name of Base Application Class', 'section' => 'Misc'),
 		'ApplicationPath' => Array ('type' => 'text', 'title' => 'Path to Base Application Class file', 'section' => 'Misc'),
 		'CacheHandler' => Array ('type' => 'select', 'title' => 'Output Caching Engine', 'section' => 'Misc'),
+		'MaxCacheDuration' => Array ('type' => 'text', 'title' => 'Maximum Cache Duration (in days)', 'section' => 'Misc'),
 		'MemcacheServers' => Array ('type' => 'text', 'title' => 'Location of Memcache Servers', 'section' => 'Misc'),
 		'CompressionEngine' => Array ('type' => 'select', 'title' => 'CSS/JS Compression Engine', 'section' => 'Misc'),
 		'WebsiteCharset' => Array ('type' => 'text', 'title' => 'Website Charset', 'section' => 'Misc', 'required' => 1),
Index: core/kernel/application.php
===================================================================
--- core/kernel/application.php
+++ core/kernel/application.php
@@ -863,17 +863,17 @@
 	}
 
 	/**
-	 * Stores new $value in cache with $key name
+	 * Stores new $value in cache with $name name.
 	 *
-	 * @param int $key key name to add to cache
-	 * @param mixed $value value of cached record
-	 * @param int $expiration when value expires (0 - doesn't expire)
-	 * @return bool
-	 * @access public
+	 * @param integer      $name       Key name to add to cache.
+	 * @param mixed        $value      Value of cached record.
+	 * @param integer|null $expiration When value expires (0 - doesn't expire).
+	 *
+	 * @return boolean
 	 */
-	public function setCache($key, $value, $expiration = 0)
+	public function setCache($name, $value, $expiration = null)
 	{
-		return $this->cacheManager->setCache($key, $value, $expiration);
+		return $this->cacheManager->setCache($name, $value, $expiration);
 	}
 
 	/**
@@ -941,15 +941,15 @@
 	}
 
 	/**
-	 * Sets value to database cache
+	 * Sets value to database cache.
+	 *
+	 * @param integer      $name       Key name to add to cache.
+	 * @param mixed        $value      Value of cached record.
+	 * @param integer|null $expiration When value expires (0 - doesn't expire).
 	 *
-	 * @param string $name
-	 * @param mixed $value
-	 * @param int|bool $expiration
 	 * @return void
-	 * @access public
 	 */
-	public function setDBCache($name, $value, $expiration = false)
+	public function setDBCache($name, $value, $expiration = null)
 	{
 		$this->cacheManager->setDBCache($name, $value, $expiration);
 	}
Index: core/kernel/managers/cache_manager.php
===================================================================
--- core/kernel/managers/cache_manager.php
+++ core/kernel/managers/cache_manager.php
@@ -73,6 +73,13 @@
 	protected $settingTableName = '';
 
 	/**
+	 * Default expiration.
+	 *
+	 * @var integer
+	 */
+	protected $maxCacheDuration;
+
+	/**
 	 * Set's references to kApplication and DBConnection interface class instances
 	 *
 	 * @access public
@@ -89,7 +96,10 @@
 				$this->settingTableName = TABLE_PREFIX . 'ConfigurationValues';
 			}
 		}
+
+		$this->maxCacheDuration = 60 * 60 * 24 * kUtil::getSystemConfig()->get('MaxCacheDuration', '');
 	}
+
 	/**
 	 * Creates caching manager instance
 	 *
@@ -97,7 +107,7 @@
 	 */
 	public function InitCache()
 	{
-		$this->cacheHandler = $this->Application->makeClass('kCache');
+		$this->cacheHandler = $this->Application->makeClass('kCache', array($this->maxCacheDuration));
 	}
 
 	/**
@@ -344,12 +354,12 @@
 		$cache_rebuild_by = SERVER_NAME . ' (' . $this->Application->getClientIp() . ') - ' . adodb_date('d/m/Y H:i:s');
 
 		if ($this->Application->isCachingType(CACHING_TYPE_MEMORY)) {
-			$this->Application->setCache('master:configs_parsed', serialize($cache));
-			$this->Application->setCache('master:last_cache_rebuild', $cache_rebuild_by);
+			$this->Application->setCache('master:configs_parsed', serialize($cache), 0);
+			$this->Application->setCache('master:last_cache_rebuild', $cache_rebuild_by, 0);
 		}
 		else {
-			$this->Application->setDBCache('configs_parsed', serialize($cache));
-			$this->Application->setDBCache('last_cache_rebuild', $cache_rebuild_by);
+			$this->Application->setDBCache('configs_parsed', serialize($cache), 0);
+			$this->Application->setDBCache('last_cache_rebuild', $cache_rebuild_by, 0);
 		}
 	}
 
@@ -510,17 +520,17 @@
 	}
 
 	/**
-	 * Stores new $value in cache with $key name
+	 * Stores new $value in cache with $name name.
 	 *
-	 * @param int $key key name to add to cache
-	 * @param mixed $value value of cached record
-	 * @param int $expiration when value expires (0 - doesn't expire)
-	 * @return bool
-	 * @access public
+	 * @param integer      $name       Key name to add to cache.
+	 * @param mixed        $value      Value of cached record.
+	 * @param integer|null $expiration When value expires (0 - doesn't expire).
+	 *
+	 * @return boolean
 	 */
-	public function setCache($key, $value, $expiration = 0)
+	public function setCache($name, $value, $expiration = null)
 	{
-		return $this->cacheHandler->setCache($key, $value, $expiration);
+		return $this->cacheHandler->setCache($name, $value, $expiration);
 	}
 
 	/**
@@ -670,15 +680,15 @@
 	}
 
 	/**
-	 * Sets value to database cache
+	 * Sets value to database cache.
+	 *
+	 * @param integer      $name       Key name to add to cache.
+	 * @param mixed        $value      Value of cached record.
+	 * @param integer|null $expiration When value expires (0 - doesn't expire).
 	 *
-	 * @param string $name
-	 * @param mixed $value
-	 * @param int|bool $expiration
 	 * @return void
-	 * @access public
 	 */
-	public function setDBCache($name, $value, $expiration = false)
+	public function setDBCache($name, $value, $expiration = null)
 	{
 		$this->cacheHandler->storeStatistics($name, 'WU');
 
@@ -687,19 +697,19 @@
 	}
 
 	/**
-	 * Sets value to database cache
+	 * Sets value to database cache.
 	 *
-	 * @param string $name
-	 * @param mixed $value
-	 * @param int|bool $expiration
-	 * @param string $insert_type
-	 * @return bool
-	 * @access protected
+	 * @param integer      $name        Key name to add to cache.
+	 * @param mixed        $value       Value of cached record.
+	 * @param integer|null $expiration  When value expires (0 - doesn't expire).
+	 * @param string       $insert_type Insert type.
+	 *
+	 * @return boolean
 	 */
-	protected function _setDBCache($name, $value, $expiration = false, $insert_type = 'REPLACE')
+	protected function _setDBCache($name, $value, $expiration = null, $insert_type = 'REPLACE')
 	{
-		if ( (int)$expiration <= 0 ) {
-			$expiration = -1;
+		if ( $expiration === null ) {
+			$expiration = $this->maxCacheDuration;
 		}
 
 		$fields_hash = Array (
Index: core/kernel/nparser/nparser.php
===================================================================
--- core/kernel/nparser/nparser.php
+++ core/kernel/nparser/nparser.php
@@ -970,12 +970,17 @@
 		return $ret;
 	}
 
-	function setCache($name, $value, $expiration = 0)
+	function setCache($name, $value, $expiration = null)
 	{
 		if (!$this->CachingEnabled) {
 			return false;
 		}
 
+		// Don't allow creating a non-expiring caches from a template.
+		if ( (int)$expiration <= 0 ) {
+			$expiration = null;
+		}
+
 		// remeber DataExists in cache, because after cache will be restored
 		// it will not be available naturally (no tags, that set it will be called)
 		$value .= '[DE_MARK:' . (int)$this->DataExists . ']';
Index: core/kernel/utility/cache.php
===================================================================
--- core/kernel/utility/cache.php
+++ core/kernel/utility/cache.php
@@ -91,14 +91,22 @@
 		var $siteKeyValue = null;
 
 		/**
+		 * Maximum cache duration.
+		 *
+		 * @var integer
+		 */
+		protected $maxDuration;
+
+		/**
 		 * Creates cache manager
 		 *
-		 * @access public
+		 * @param integer $max_duration Maximum duration.
 		 */
-		public function __construct()
+		public function __construct($max_duration)
 		{
 			parent::__construct();
 
+			$this->maxDuration = $max_duration;
 			$this->siteKeyName = 'site_serial:' . crc32(SQL_TYPE . '://' . SQL_USER . ':' . SQL_PASS . '@' . SQL_SERVER . ':' . TABLE_PREFIX . ':' . SQL_DB);
 
 			// get cache handler class to use
@@ -145,15 +153,20 @@
 		}
 
 		/**
-		 * Stores value to cache
+		 * Stores new $value in cache with $name name.
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration cache record expiration time in seconds
-		 * @return bool
+		 * @param integer      $name       Key name to add to cache.
+		 * @param mixed        $value      Value of cached record.
+		 * @param integer|null $expiration When value expires (0 - doesn't expire).
+		 *
+		 * @return boolean
 		 */
-		function setCache($name, $value, $expiration)
+		function setCache($name, $value, $expiration = null)
 		{
+			if ( $expiration === null ) {
+				$expiration = $this->maxDuration;
+			}
+
 			// 1. stores current version of serial for given cache key
 			$this->_setCache($name . '_serials', $this->replaceSerials($name), $expiration);
 			$this->storeStatistics($name, 'W');
@@ -599,13 +612,13 @@
 		/**
 		 * Stores value in cache
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration
-		 * @return bool
-		 * @access public
+		 * @param string       $name       Name.
+		 * @param mixed        $value      Value.
+		 * @param integer|null $expiration Expiration.
+		 *
+		 * @return boolean
 		 */
-		abstract public function set($name, $value, $expiration = 0);
+		abstract public function set($name, $value, $expiration = null);
 
 		/**
 		 * Stores value in cache (only if it's not there already)
@@ -686,13 +699,13 @@
 		/**
 		 * Stores value in cache
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration
-		 * @return bool
-		 * @access public
+		 * @param string       $name       Name.
+		 * @param mixed        $value      Value.
+		 * @param integer|null $expiration Expiration.
+		 *
+		 * @return boolean
 		 */
-		public function set($name, $value, $expiration = 0)
+		public function set($name, $value, $expiration = null)
 		{
 			return true;
 		}
@@ -783,13 +796,13 @@
 		/**
 		 * Stores value in cache
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration
-		 * @return bool
-		 * @access public
+		 * @param string       $name       Name.
+		 * @param mixed        $value      Value.
+		 * @param integer|null $expiration Expiration.
+		 *
+		 * @return boolean
 		 */
-		public function set($name, $value, $expiration = 0)
+		public function set($name, $value, $expiration = null)
 		{
 			// 0 - don't use compression
 			return $this->_handler->set($name, $value, 0, $expiration);
@@ -854,13 +867,13 @@
 		/**
 		 * Stores value in cache
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration
-		 * @return bool
-		 * @access public
+		 * @param string       $name       Name.
+		 * @param mixed        $value      Value.
+		 * @param integer|null $expiration Expiration.
+		 *
+		 * @return boolean
 		 */
-		public function set($name, $value, $expiration = 0)
+		public function set($name, $value, $expiration = null)
 		{
 			return apc_store($name, $value, $expiration);
 		}
@@ -933,13 +946,13 @@
 		/**
 		 * Stores value in cache
 		 *
-		 * @param string $name
-		 * @param mixed $value
-		 * @param int $expiration
-		 * @return bool
-		 * @access public
+		 * @param string       $name       Name.
+		 * @param mixed        $value      Value.
+		 * @param integer|null $expiration Expiration.
+		 *
+		 * @return boolean
 		 */
-		public function set($name, $value, $expiration = 0)
+		public function set($name, $value, $expiration = null)
 		{
 			return xcache_set($name, $value, $expiration);
 		}
@@ -974,4 +987,4 @@
 		{
 			return xcache_unset($name);
 		}
-	}
\ No newline at end of file
+	}
Index: core/kernel/utility/system_config.php
===================================================================
--- core/kernel/utility/system_config.php
+++ core/kernel/utility/system_config.php
@@ -68,6 +68,7 @@
 			'ApplicationClass' => 'kApplication',
 			'ApplicationPath' => '/core/kernel/application.php',
 			'CacheHandler' => 'Fake',
+			'MaxCacheDuration' => 30,
 			'CmsMenuRebuildTime' => 10,
 			'DomainsParsedRebuildTime' => 2,
 			'EditorPath' => '/core/ckeditor/',
Index: core/kernel/utility/unit_config_reader.php
===================================================================
--- core/kernel/utility/unit_config_reader.php
+++ core/kernel/utility/unit_config_reader.php
@@ -224,10 +224,10 @@
 
 			if ( $cache ) {
 				if ( $this->Application->isCachingType(CACHING_TYPE_MEMORY) ) {
-					$this->Application->setCache('master:config_files', serialize($this->configFiles));
+					$this->Application->setCache('master:config_files', serialize($this->configFiles), 0);
 				}
 				else {
-					$this->Application->setDBCache('config_files', serialize($this->configFiles));
+					$this->Application->setDBCache('config_files', serialize($this->configFiles), 0);
 				}
 			}
 		}
Index: core/units/helpers/category_helper.php
===================================================================
--- core/units/helpers/category_helper.php
+++ core/units/helpers/category_helper.php
@@ -209,10 +209,10 @@
 			$data = $this->_getChildren($root_category, $languages);
 
 			if ( $this->Application->isCachingType(CACHING_TYPE_MEMORY) ) {
-				$this->Application->setCache('master:StructureTree', serialize($data));
+				$this->Application->setCache('master:StructureTree', serialize($data), 0);
 			}
 			else {
-				$this->Application->setDBCache('StructureTree', serialize($data));
+				$this->Application->setDBCache('StructureTree', serialize($data), 0);
 			}
 
 			return $data;
@@ -274,10 +274,10 @@
 			}
 
 			if ( $this->Application->isCachingType(CACHING_TYPE_MEMORY) ) {
-				$data = $this->Application->setCache('master:template_mapping', serialize($mapping));
+				$data = $this->Application->setCache('master:template_mapping', serialize($mapping), 0);
 			}
 			else {
-				$this->Application->setDBCache('template_mapping', serialize($mapping));
+				$this->Application->setDBCache('template_mapping', serialize($mapping), 0);
 			}
 
 			return $mapping;
Index: core/units/helpers/menu_helper.php
===================================================================
--- core/units/helpers/menu_helper.php
+++ core/units/helpers/menu_helper.php
@@ -143,10 +143,10 @@
 					$menu['parentPaths'] = $this->parentPaths;
 
 					if ( $this->Application->isCachingType(CACHING_TYPE_MEMORY) ) {
-						$this->Application->setCache('master:cms_menu', serialize($menu));
+						$this->Application->setCache('master:cms_menu', serialize($menu), 0);
 					}
 					else {
-						$this->Application->setDBCache('cms_menu', serialize($menu));
+						$this->Application->setDBCache('cms_menu', serialize($menu), 0);
 					}
 				}
 
Index: core/units/helpers/sections_helper.php
===================================================================
--- core/units/helpers/sections_helper.php
+++ core/units/helpers/sections_helper.php
@@ -203,10 +203,10 @@
 			$this->Application->HandleEvent(new kEvent('adm:OnAfterBuildTree'));
 
 			if ( $this->Application->isCachingType(CACHING_TYPE_MEMORY) ) {
-				$this->Application->setCache('master:sections_parsed', serialize($this->Tree));
+				$this->Application->setCache('master:sections_parsed', serialize($this->Tree), 0);
 			}
 			else {
-				$this->Application->setDBCache('sections_parsed', serialize($this->Tree));
+				$this->Application->setDBCache('sections_parsed', serialize($this->Tree), 0);
 			}
 		}
 
@@ -378,4 +378,4 @@
 			}
 			return $ret;
 		}
-	}
\ No newline at end of file
+	}
Index: core/units/helpers/site_helper.php
===================================================================
--- core/units/helpers/site_helper.php
+++ core/units/helpers/site_helper.php
@@ -85,10 +85,10 @@
 					$cache = $this->Conn->Query($sql, 'DomainId');
 
 					if ($this->Application->isCachingType(CACHING_TYPE_MEMORY)) {
-						$this->Application->setCache('master:domains_parsed', serialize($cache));
+						$this->Application->setCache('master:domains_parsed', serialize($cache), 0);
 					}
 					else {
-						$this->Application->setDBCache('domains_parsed', serialize($cache));
+						$this->Application->setDBCache('domains_parsed', serialize($cache), 0);
 					}
 				}
 			}