one repository to store them all (Score 1)

poor environments (like some RAD tools) which store source code in binary formats and/or where you would have to trigger exports manually to get to the code could be reasons for not using a repository. those tools must be easy to use, e.g. being integrated with your IDE or you simply would not use them.

_all_ my documents go into Subversion: source code, office documents (text, spreadsheet, presentation), pdf manuals, invoices...
easy to back up and keep consistent over all machines.