Starting in October, the Library will send overdue notices, recall notices, and book available notices to Pitt e-mail addresses rather than by campus mail or US mail. If you don't use your pitt.edu address and don't get an overdue notice, you could be looking at some hefty fines.
Already your professors try to contact you by Pitt e-mail through Courseweb and Peoplesoft; and when people look you up on the pitt.edu directory, they find your Pitt e-mail.
So if you are not regularly checking your pitt.edu address, you should be!
And if it's full of old messages and over quota so that messages to you bounce back to their sender, it's time to clean it out.