Zend is kind of bloated and tries giving you the world when you only need a form parser. require_once is also "slow" because it checks the list of required files each time you call require_once to make sure you aren't requiring the same file twice. It makes sense to stay away from that with a framework like Zend where it just wants to include so many files. With your typical app, not using require_once and only using require probably doesn't save much time