When you actually have a subscription for RHEL, you can also get email notifications whenever security fixes, bug fixes, and/or feature enhancements are release

When you actually have a subscription for RHEL, you can also get email notifications whenever security fixes, bug fixes, and/or feature enhancements are released for packages that are installed on your servers. There is some configuration you can do to pick what events you get notified for (like bug fixes only). And if you find yourself managing an enterprise environment, Red Hat Satellite (basically on-premise RHN + promotion/environment/configuration management) tracks what errata are applied to or required by each system and can report on what the gaps are. I work for Red Hat, and making it easy to support Linux is definitely our bread and butter.