One of the best questions to ask during an interview for a new Flex developer is how to handle memory management in Flex. You can immediately gauge someone’s competence (how they handle memory issues) and experience (if they’ve had to handle memory issues on large projects) with this single question.
If someone fails to answer this question adequately, it’s an immediate red flag that the interviewee probably isn’t hiring material.
A good answer involves weakreferences, methods to cleanup or dispose of all references to a class/object, reusable renderers and sometimes using Grant Skinner’s Janitor class.
Grant Skinner has also published an good overview presentation on memory management here.