Modern documentation: Wiki, live docs, repos
The thing about documentation is that everyone admits that it is important, everyone talks about it, and almost no one does it or if they do, they don't keep it up to date. Documentation is boring, often harder than it seems to do well, and because almost no management will ever follow up and verify it, extremely easy to ignore. No one ever gets promoted because of excellent documentation, no one throws documentation parties, and no one talks about it on their curriculum vitae. Documentation just is not cool enough for people to want to spend time talking about.
Documentation is, however uncool it might feel, amazingly important for so many reasons. It can go far for moving someone from being an acceptable system administrator to being a great one.
Documentation does some interesting things. Of course, it allows us to recall how systems work and what tasks need to be done to them. It allows us to hand off tasks to others. It...