What are the advantages and disadvantages of using the GAC?

Question

And on top of that, are there cases where one has to use the global assembly cache or where one cannot use it?

Answer 1

In all my life, I have had maybe one application where I had to put an assembly in the GAC, simply because these assemblies were part of a framework that a number of applications would use it, and it seemed right to put them into the GAC.