A single repository?
Ideally, all content should be placed in a single repository, such as Git version control software. This maximizes reuse, consistency, and quality. If the content is in DITA XML or DocBook format, for example, the single-sourcing capabilities of these formats can be fully exploited to publish the content in the appropriate form.
Content becomes a network of information modules, and the relationships within this network need to be managed, particularly during updates.
Single Repository
In practice, it appears that very few companies have taken this step. It is true that until structured formats are taught earlier in education, it seems unrealistic to expect all team members within a company to adopt them, especially if employee turnover is high.
Additional resources