stdafx.h: When do I need it?

Question

I see so much code including stdafx.h. Say, I do not want pre-compiled headers. And I will include all the required system headers myself m

Answer 1

Even without pre-compiled headers stdafx.h could be handy as it groups header includes and definitions common for all files.

You can of course choose to repeat all these definitions in every file. stdafx.h is not strictly necessary.