Life was so much simpler when I had only one email address. Now I have three: one for managing online accounts, another for personal correspondence, and a TidBITS email alias for work email.
The email itself isn’t difficult to manage, but it’s a pain when a TidBITS contributor shares a Google Docs-hosted article draft with me via my TidBITS email alias, which isn’t a Google account, and I get the dreaded “You need permission” error, preventing me from accessing the document.
Fortunately, there’s an easy way to, and once that’s done, documents can be shared with any associated address. Visit the  settings page for your Google account (you’ll have to enter your password), and then, under “Other Emails,” click the Edit link.
That takes you to the Manage Account Information page, with a text field at the bottom in which you can enter an alternate email address. Input an address, click Save, and Google sends a verification email message to that address. After you click the link in that message, that email address will be associated with your Google account, and will work when someone shares a Google Doc with it. Should you wish to remove an associated email address, return to the Manage Account Information page and click the X to the left of the email address you want to delete.
Unfortunately, an email address can be associated with only one Google account at a time. Since every Gmail address maps directly to a Google account, you can’t associate a Gmail address with another Google account. And, as with Apple IDs, there is currently no way to merge Google accounts. (Come on, guys, acknowledge that you messed up in allowing or even requiring multiple accounts in the distant past and let us merge them!)
This method of associating alternate email addresses with your primary Google account removes some of the annoyance from using multiple email accounts, but there are other minor benefits as well. For instance, you can sign in to Google services using the alternate email address (in most cases — we have seen occasional exceptions where the primary address must be used), and they can also be used to recover your password in an emergency.