Program icons: generic vs. branded

[Friedrich W. H. Kossebau]

Hi,

what is the correct way to choose a program's icon?

Searching through techbase and looking at different program.desktop files did 
not help me to find a pattern.

The icon naming spec says:
"Icons that describe what an application is, for use in the Programs menu, 
window decorations, and the task list. These may or may not be generic 
depending on the application and its purpose. Applications which are to be 
considered part of the base desktop, such as the calculator or terminal, 
should use the generic icons specified in this specification, while more 
advanced applications such as web browsers and office applications should use 
branded icons which still give the user an idea of what function the 
application provides."
http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html

I find the definition of programs which should use generic icons very 
unprecise. What is a "more advanced" program? And what is the reasoning for 
generic icon (names) for programs?

Some programs follow the spec, like Okular (graphics-viewer-document) and Ark 
(utilities-file-archiver), others like KCalc (kcalc) don't. But isn't Okular 
a more advanced program, while KCalc isn't?

Does KDE follow the spec? How do I find out if e.g. Okteta, the new hex editor 
in kdeutils :) , should use a branded icon or a generic one?

If the reason for generic icon names are icon themes, well, what about using 
names like graphics-viewer-document-okular and utilities-file-archiver-ark? 
So if the branded icon is not included in the icon theme the fallback will be 
the generic one?

Oh dear, a lot of questions. :)

Thanks
Friedrich