Having only tiny loft space, an already full garage, and shed intended for other things, I keep only boxes that I think I will need, whether hi-fi, or anything else. Buying most hi-fi gear secondhand, often not having manufacturers’ boxes, minimises boxes! The smaller boxes, I do keep in the tiny bit of loft. Both my last speakers and current ones that I bought only six months ago came in the original boxes, which I have kept. With the speakers being relatively large floorstanders, they are big boxes! I collapsed them and put in the shed, the flattened cardboard against the wall, and the packing pieces/spacers bundled together as best I could, wrapped tightly with plastic to hold together, and also in the shed. Not ideal as still occupies space, but if I were to move house, let alone sell the speakers, they would be invaluable for protecting them. (Last time I moved house with large speakers, without boxes, I had to build something to protect them while manhandled in transit.
Its bad enough keeping a load of Naim boxes. I also have the boxes and bits for 2 x 802 D2s as well.
All that cardboard does not come cheap. it does help when P/Xing with your dealer.
Keep them all as a rule but … In house 1 … I kept ALL the DBL boxes and when the time came … back in to their boxes they went, and off to house 2. In House 2 … Oh, I tried, I really tried, trust me … but have you seen these things? The Base boxes had to go in the outside shed where sadly they disintegrated a few years later. But to the eventual new buyer I could at least offer ALL the foam packing, plus the boxes for the bass units and HF/MF units. And guess what … they wouldn’t fit in his vehicle, so it was, stuff it mate, just help me load the speakers in, we’re fine
The boxes can also be used to store other things that need storage and save space but comment has been made about the number of boxes I have in cupboards.
I generally store them when nobody is looking. It’s hard to get into a conversation that might touch on saying ‘of course I keep the boxes - do you have any idea how much these things cost!’
Again? I’m only just getting used to the Classic boxes being bigger than the Olive ones.
To answer to original question, I would keep them all and collapse them. They are usually held together with those big staples. Although you will still need to keep the foam bits.
I keep all the boxes for anything I’ve bought and may want to either sell or get serviced.