Mary Charles Lasater mentions:
"A few ‘best practices’ might be useful. "
With which I wholeheartedly agree.
Locally, I have established a few "best practices." For example, we put extra effort into authority records for certain categories, such as entities affiliated with the University and special collections. Hence, I would include our institution in a 373 field for faculty authors. We have a special collection of women composers, so I include a 374 field for them, in the hope that someday (soon?) this field will enrich searching.
But, of course, more widely agreed upon best practices would make a lot more sense. We are all about cooperation, aren't we?