drivers have to be installed on C
windows updates have to be installed on C (though windows has been known to use other space for the image files)
there are ways to make windows change the default save location but windows isn't smart, it uses that location for everything so it breaks windows by doing it.
you can install anything anywhere but it just gets messy. Installing programs on D drive and then reinstalling windows leaves all the files still on D and only real thing left to do is delete the application folder as you can't use it on new install.
Almost every program you install creates an entry in the
Registry and that is main barrier to reusing previously installed programs, the new registry has no idea about the old programs and manually entering them is not an easy task. I don't even try.
Some things don't, many games you can reuse again. Steam games are easy to reuse or even move around on drive. Shame Microsoft Games are complete opposite. I used to always install my windows library folders on 2nd drive as you can reuse things like music and pictures as many times as you like.