deborphan was removed from development, but if you are using current stable you still can use it. It’s awesome. It identifies packages installed but probably not needed.

apt install deborphan

apt install localepurge

to delete translation files not needed

Very useful. Thanks.

stable and new stuff on unstable.

A becomes B. But… you have a lot of options in case you want a different behavior.

• dunno
• yes
• yes

(just to add, and clarify - no more than 2 disks)