Book Smart: Knowing that separate development, test, and production environments should be as identical as possible.

Street Smart: Realizing that depending on the purpose & goals of the development and test environments, “identical” may only refer to the OS, and you might only need physical hardware for production, if even that.

Book Smart: A vendor says a software upgrade on a storage array will take two hours.

Street Smart: The vendor is only talking about successful, optimal upgrades, and you schedule additional time for handling whatever goes wrong.

Book Smart: Operating system patches don’t change functionality.

Street Smart: The people that put OS updates together are human and make mistakes, like overwriting configuration files, messing permissions up, or omitting a package dependency.