<p>I am suggesting that students should use school applications whenever they are available. There were many who thought they could write better an essay after they submitted common app early for EA/ED or forgot to put something in. Expressed interest does matter, even at Princeton/Harvard/Yale. Admission officers are not GODS and they do have feeling towards their school. Try to tell them that Princeton is not your top choice to see how far you can get. Even if it only matters a little, there is no reason not to use PA. Of course, P will accept come CAs just to show they do accept CA to keep applicant pool large. Many highly qualified applicants get rejected and lack of interest is one of the reason among many other reasons.</p>