I think 5tons made a good point though. In the web world , unless you are dealing with some serious levels of data , ie a sears catalog , where you have to parse a 250,000 line xml doc to generate image objects as children , we are speaking in the 10th of a second range as far as process time. And yes in most RIA scenarios , ref's vs events from a physical memory standpoint are probably not going to make a difference. I understand the referencing an object doesn't create a new one , but its having to re access that same chunk of data , more frequently and at a much higher level then if it was solely event driven. The events are handled deeper within the framework of a flash movie , in the more primitive areas of the compiled code.