It happened to an application I released (PHP and CakePHP) that once got into production environments, there were some caching problems. For example after a login, the menu didn’t get the correct profile and with a simple refresh (CTRL+R) of the browser everything is solved.
Well in order to solve this problem I added to whole pages (app/views/layouts/default.thtml for the framework) the following code
header("Expires: " . gmdate("D, d M Y H:i:s") . " GMT");
<meta http-equiv="pragma" content="no-cache" />