James Ward of Adobe posted a good idea to reduce size of Flex 2 applications. He suggested it could be used to load some static url runtime shared library for Flex applications, so only the first time this(these) file downloaded will ask load time, if that file is still cached ( browser cached as well as external cache servers), individual Flash applications which use the same components could be loaded fast after cutting those common-in-use parts.

The same it could be used for Flash 9 development but mostly only for regular class packages like effects and should make sure it was loaded each time. (Unlike Flex a film effects Flash couldn’t allow preloader in most case).

Maybe it will be even better after Apollo available, to have some local access libraries and run with Apollo.