The skill to distinguish durable/persistent documentation from disposable/perishable documentation.
Durable documentation is revisable and governable via Draft, Review, Revise, Approve, Distribute. Disposable documentation ... someone might look at it within a couple weeks, but no one is going to formally revise and approve the documentation.
Durable documentation: process flows, GUI design, training materials, go-live announcements, standardizable project plans. Durable documentation is scalable communication. Not reinventing the wheel.
Disposable documentation: meeting minutes, micro-managed action items, "notes." Just evidence that "people talked." Disposable documentation is not very scalable. Likely reinventing the wheel.