Avoid duplication
If something is written once and you can easily link to it, use the link. Duplicate content produces poor search results, confuses the user, and it can be hard to catch and update all of it..
If users can find two similar yet slightly different pieces of content they will stop what they are doing and ask for guidance. Worse, what if the user decides the first one found is correct, or the one with the latest date should be used?
Your organization may have hundreds of file folders on many, many servers. That's a lot of content needlessly duplicated. Consolidate. Direct the reader to the right location — ask someone if you aren't sure.
Before you start writing, check to see it hasn't already been written. Ask someone!