We have a solution with around 100+ projects, most of them C#. Naturally, it takes a long time to both open and build, so I am looking for best practices for such beasts. Along the lines of questions I am hoping to get answers to, are:

• how do you best handle references between projects
  • should "copy local" be on or off?

• should every project build to its own folder, or should they all build to the same output folder(they are all part of the same application)

• are solutions folders a good way of organizing stuff?

I know that splitting the solution up into multiple smaller solutions is an option, but that comes with its own set of refactoring and building headaches, so perhaps we can save that for a separate thread :-)