You have been using Calibre about as long as I have. I started about a month before my EZReader pocket Pro was delivered.
I already had all the BAEN CD's and I wanted to be ready
If ??? You have not discovered these plugins...RUSH to the Preferences Icon: right click: Get Plugins.


#1-10) Quality check Plugin . I put the -10 because you will USE so many of the items that this does
to FIND issues with your (stock) metadata.
Then the
FIX section can flip those Authors the have comma issues

. Reformat initials to your rules
#11 Find Duplicates
#12 Manage Series Allows re indexing and consistent name for the selected group
#13-17{now it get harder to choose}: Search the Internet (for details not in found metadata), Import List , Count Pages, Resize cover (I don't keep HD size covers), Generate Custom Cover (lots more options than the MDE one offers),
A bunch that are device specific (Kindle, Kobo)
and the one that is NOT here (See Alf for that one

)