If you're going more than a month without updating a server, then you should allow for the possibililty of a bit of downtime (or delay to read the docs) when you do get around to updating it. And since it wasn't clear in the article: removing a package from the portage repo doesn't cause the package to be automatically uninstalled from your system, and it doesn't cause the package to be ignored during dependency resolution.
More than a month without an interactive login, sure.