helper,libraries autoload or when need

[eluser]umefarooq[/eluser]
Hi
which one is the best way to use libraries,helper and other using auto load or load it in when it need, if we put in autoload it include all helper and libraries will it slow down the performance of the application.

[eluser]xwero[/eluser]
You autoload files if you need them system wide otherwise load them when needed.

[eluser]drewbee[/eluser]
Exactly, I know that I will always need the session and database classes on every single page (including AJAX requests), so those two are always auto loaded.