Mods as a whole is a big tent kind of word. For some, it’s a shaker and Color DMD and for others, it’s Star Wars action figures. I agree with snakesnsparklers and take the game as a whole.
As a buyer, I decide if it’s worth it to me or not. If not, no big deal, I don’t reach out to the seller. No harm done there.
As a seller, I tend to remove things like a shaker, speaker lights or color DMD before listing them as I can easily move them to my next game. I leave Titan Rubbers, plastic protectors and game specific items.
It also depends on the sale. What I stated above is mostly for a public listing. If dealing with an acquaintance or friend, it’s different.