How to manage multiple email addresses?

For some reasons you applied many email addresses，but you may not have time to browse and manage these email boxes？but you don't want to give them up, but eventually you might forget them. what would you do？

1. set up forwarding function of your email，let it forward any incoming emails to the email address you often care。
2. If you really want to abandon some email address, set up the auto reply function, let senders know your formal email address you want to maintain.