Everything Chaley said
(BTW the examples were the first group I had to clean up.) My Hierarchy choice was the Major class of the work and the dot part, the REFINED partition. Science Fiction.Military (not the reverse)
Searching on either term will find members. No need for alternate tags (like in that old card file)
You need a PLAN, then fix what you have. Standardize tags. Many of the variation were holdover mentality fro days past where there was a card catalog in the room.
Calibre has a
Tag Mapper, that can be used when ADDING BOOKS (Preferences: Adding books: Adding Actions (a tab): control... )
AFAIK this does NOT affect downloaded metadata <hint hint: option to use
> or existing books
Another Fix I do is reset Plurals to a singular (Detectives -> Detective ).
I also separate double groups: Science Fiction & Fantasy becomes Science Fiction, Fantasy (or I drop the one Manually when it does not really apply )
Even with all this, I have way too many tags
and researching for this, I need to do another house cleaning
