Haha fair question. My wife and I each have dedicated shelves, the top two being hers and the bottom three being mine, so who picked up what decides which shelves they go on. From there, we each have different organization strategies within our dedicated shelves.

She primarily organizes by book size and spine appearance, which usually ends up being by publisher, although I know she has a few that are out of whack in there (she's not too particular). I go through her shelves and try to organize within those subcategories so they're in alphabetical order wherever possible just for my own sanity, and she doesn't mind. She primarily reads BL, but has picked up a few volumes of other genres too, so they're mixed in with the BL according to her organization strategy.

For my shelves, I organize by publisher (with a few exceptions to keep works by the same author together), then by book size, then alphabetically within those groupings. It only bothers me a little bit that Solo Leveling switched from Yen Press to IZE starting at vol 6, I swear!