Test for Good Software Design (C++ precompiled headers are an excuse)

Here is a great and simple test for good C++ design.
If you have to add a header file for a new class or structure to one module, does it cause many other unrelated C++ files to be recompiled?
You had to add the header include to another header that is included by lots of .cpp files.
Precompiled headers are used as an excuse for bad design.