There are a number of scenarios in which it may be beneficial to cache a form rather than parse an XFL document each time the page is loaded. An example scenario that would merit the caching of a form would be a comment section on a blog. In this case a page may be loaded 100s of times without the form being used and each time requiring the form to be loaded. In cases such as this, forms can be cached with a number of packages such as APC and Xcache. It would be advisable to use APC as it is being added to the PHP core in PHP 6.