To be brutally honest, if you have so much content installed, I would seriously doubt that most of that is utilized on a regular basis.  The issue here is maintenance, and the ultimate solution would be databasing your content and only installing what you absolutely need for your current project and uninstalling them afterwards.  If you don't use the content within 6 months, chances are you may not need it.  Probably not what you would like to hear, but may be true. 

I maintain a database, organized by several categories.  I, also, have several RT's organized by categories.  Content is installed by need and usage only, although most DAZ characters occupy one main Poser folder.  Once I am done with a specific project, the content will linger for a time before I retire it indefinitely.