Cats do not get bored of cardboard. They get bored of the same cardboard in the same place in the same shape, which is why a delivery box can be the centre of a cat's world on Monday and invisible furniture by Friday, and why rotation, not shopping, is the whole technique.
How One Box Lives Three Lives
Use each box in stages. First it is furniture: a new object in the room to be inspected, rubbed against and sat in exactly as it arrived. A few days later, change its job by cutting a new doorway in another side, turning it into a den with an entrance she has to discover and an inside that feels different because the light and the approach have changed. Add a paper bag tunnel against the entrance or a scrunched paper ball inside and the den becomes a hunting site instead of a bed.
Then retire it before it turns boring, while she still values it, and put it out of sight with the rest of the stock. Absence restores novelty far more cheaply than novelty itself: a box returning after a week away is greeted like a new object, while a box left out permanently is walked past. Keep the cycle ruthless, because the temptation to leave her favourite out is exactly how favourites die.
The Rotation Rhythm and the Stock
Keep a modest stock: a few boxes in different sizes, plain paper bags, cardboard scratchers, scrunched paper and a sturdy tube if one comes your way. Swap two or three items every few days, changing what is on the floor rather than adding to it, so the room always holds a small fresh set instead of a clutter of stale ones. A cat explores contrast; three changed items beat ten unchanged ones, and a tidy rotation is easier to keep up than a sprawling one nobody maintains.
Hide a few pieces of her normal food inside the items as you set them out, tucked into the den, under the bag, inside the tube. Food hidden like this turns inspection into foraging, which stretches a thirty-second sniff into minutes of searching, and it costs nothing beyond food she was going to eat anyway. Rotate the hiding logic too, so the search stays a search: food always in the box teaches her to check the box and ignore everything else.
Safety Checks Before Anything Is Offered
Every item gets the same safety pass before it reaches her, because the dangers in household enrichment are ordinary and easy to miss. Work through the set every time: handles, staples, tape, plastic and string removed before any item is offered. Bag handles come off entirely rather than being tucked in, staples are pulled from box flaps, tape strips come away with the labels, plastic wrapping never reaches the floor pile, and string, ribbon and elastic are excluded outright rather than supervised, because a swallowed length is a vet emergency, not a play style.
Check the box itself as well: thick tape seams can peel into chewable strips, and a box that has carried cleaning chemicals or anything scented is recycling, not enrichment. Retire items that are collapsing into small chewable pieces, and keep the whole game away from anywhere she could bring a structure down on herself. KinsLe's Care Teams lets the household share who restocks the box stash and when, with each finished task timestamped so no swap gets missed or doubled.