It's generally a good idea to have some documentation that states what a machine is used for, the "service", and how important said service is relative to other

It's generally a good idea to have some documentation that states what a machine is used for, the "service", and how important said service is relative to others. At my company we kind of enforce this by not operating machines that are not explicitly assigned to any service. However you have to anticipate that the quality of documentation still varies immensely which might result in you shutting down a service that is actually more important than stated. Fortunately documentation improves after every outage because service owners reiterate on their part of the documentation when their service was shut down as "it appeared unimportant". It's a process.