The emails disappear from the iPhone after about half to one hour after it gets them from the server even if they are not read. I have two different email accounts and my iPad and iPhone both poll the accounts at regular intervals. The emails stay on the server until I download them on my home computer this allows me to get them when they arrive while I am away from home. It has been working this way for a number operas untill a couple of days ago. The emails are not disappearing from my iPad just the iPhone.