Recently, a classmate let me know she had found an email from me at her old email address. To ensure that doesn't happen again she used the online address update process found on the Email Directory page of the class web site to ensure her alumni address information was current.
Her actions were precisely the right thing to do. By asking each classmate who is online to keep their address info current, and making that a very easy thing to do, most of the choke points that have contributed to alumni address information being out-of-date have been significantly reduced.
The online approach allows each classmate with access to an Internet connection to update their alumni information with a minimal effort, usually only about two minutes or less from start to finish. I encourage everyone who hasn't done so already to go to the Email Directory page of the class web site and use the Update Address form. And use it each time any part of your address information changes.