I have a web page that has many forms. One for logging in, another for creating an article and another for submitting a comment. Now, each of these forms is backed by a different backing bean for instance: loggingBean, newCommentBean, etc. When the life cycle executes, does it create instances of each of these beans even though the user submitted only the "new comment" form?
It all depends on the scope of the beans. Request beans are created once per request but you probably shouldn't worry about the overhead of a bean creation, it's tiny. You should usually be more concerned with beans staying around too long (session beans that should be request beans) which needlessly drains memory.