I am currently developing a page where I have to render some fields dynamically based on the value of a poplist. Initially I was setting the rendered property to true or false based on the value of another field using EL expression and partial triggers is set to the id of the poplist. But this did not work as expected because partial triggers will not work on components that are not rendered (rendered = false). So a round about solution I used was , I gave partial triggers to the entire region in which my dynamic component is present.But this resulted in unnecessary validations because the entire region is refreshed unnecessarily.
Then through forums, I came to know that I have to use visible property instead of rendered property in my case to dynamically render or hide the field. By doing so, I can keep the partial triggers to the current field itself instead of using ppr for entire region in which it is present.
So the moral of the story is… in a scenario like this, use visible property instead of rendered property.