Keep the old litter box during the transition for at least one to two weeks after the new automatic box goes in. That is the floor, not the finish line. The honest answer is not a date on a calendar: only remove the old box once your cat is using the new one consistently, confidently, and without incident across several days in a row. If that has not happened by day fourteen, the old box stays right where it is.
I ran this setup with three cats, Mao, Leo, and Deo, and each hit that point on a different day. Two cleared it inside a week. One took closer to three. Pulling it on day ten for everyone would have been a guess for the cat who still needed it. This piece covers the floor, what "ready" looks like, and how to step the old box out instead of switching it off in one move. If you have not started the switch yet, my week-one method for introducing the box powered off is the starting point before this applies.
The One-to-Two-Week Minimum, and Why It Is a Floor, Not a Target
The one-to-two-week figure is not something I invented. It shows up consistently across vendor guidance and independent advice as the standard hold-both-boxes window before removal is worth considering. Whisker, the company behind Litter-Robot, does not publish a hard number on its own acclimation page. Instead it tells owners to let the cat use both boxes for a period of time, gradually cleaning the old one less often until the cat relies on the new one by choice. That is a readiness-based instruction wearing the clothes of a timeline, and the more honest version of the two.
Treat one to two weeks as the earliest you are allowed to ask the readiness question, not the day you act on it automatically. A confident cat might be ready inside a week. A cautious one, especially in a multi-cat home where the new box is new territory to negotiate, can need longer. The full range of that timeline, and what pushes a cat into the slower band, is covered in how long acclimation actually takes, so I am not repeating that table here.
The Readiness Check
Here is the actual test, and it replaces the calendar entirely. For at least three to four consecutive days, your cat should walk into the new box on its own, use it without hesitating at the entrance or bolting out mid-use, and skip the old box entirely, not even a sniff. One good day is not a pattern. A cat can have a fluke smooth visit and then avoid the box the next day if something startled it mid-cycle.
Watch for the absence of drama, not the presence of enthusiasm. A cat that walks in, does its business, and walks out without hovering by the door first has passed. A cat that still detours to the old box occasionally, even when it is available, has not, and that occasional use is information, not stubbornness. It is telling you the new box has not fully earned the cat's trust yet, and removing the option before that trust exists is how elimination ends up somewhere else in the house entirely.
How to Step Down, Not Switch Off
Once the readiness check passes, do not pull the old box in one move. Step it down instead. Move the old box a foot or two from its usual spot, then a bit further every day or two, watching that use of the new box does not drop off as you go. At the same time, let the old box get a little less clean than usual, since a slightly less appealing option nudges the choice toward the new one without forcing it.
Only after several days of the old box sitting further away, less fresh, and still going unused should it actually leave the house. This staged approach costs more patience than pulling the box out the day the readiness check passes, but it gives a cat one more quiet chance to object, by using the fading box again, before removal is final. In a three-cat home, that staged window matters because one cat's full commitment does not guarantee it for the other two.
Signs You Removed the Old Box Too Soon
If the old box came out and something changed, elimination near where it used to sit, a cat pacing or seeming to hold it, or one cat suddenly guarding the new box, it came out too early or too fast. This is not a failure, and it is not a reason to restart the introduction. Bring the box back to its previous spot, resume normal cleaning on both, and give it another week before repeating the check.
One caveat, stated plainly. If the change in bathroom behavior includes straining, frequent short trips, blood, or a cat that seems to be in pain, that is not a transition problem, and backtracking will not fix it. That pattern needs a vet, not a litter box, and I am not covering it here. My guide to getting a cat to accept a self-cleaning box covers the full method this check sits inside, and if choosing a unit for more than one cat is still the open question, my guide to self-cleaning litter boxes for multiple cats is the place to start first.
FAQ
Is it safe to remove the old litter box after exactly one week?
Sometimes, but do not assume it by default just because a week has passed. One week sits inside the standard floor, and a confident cat can genuinely be ready by then. Run the readiness check first: several consecutive days of calm, independent use of the new box with no return visits to the old one. If that pattern has not shown up yet, wait, even if the calendar says a week is enough.
Can I remove the old box for just one cat in a multi-cat home and leave it for the others?
Not cleanly, no. Cats share territory and options in a multi-cat home, so pulling the old box changes what is available to every cat in the house, not just the one who is ready. The safer move is waiting until the most cautious cat clears the readiness check, or keeping a reduced hybrid setup running longer for that one cat's sake while the others manage fine without it.
What if my cat still uses the old box occasionally after two weeks?
Occasional use after two weeks is a real signal, not a quirk to shrug off. It usually means something about the new box, its placement, the litter type, or the noise it makes, is still not fully trusted. Do not remove the old box on schedule anyway just because two weeks have passed. Look at what might be driving the occasional return first, and only remove the old box once that visit stops entirely.
Does moving the old box before removing it confuse the cat?
A little relocation over several days is expected, and it is part of the point: it lets the cat notice the change gradually instead of all at once. A sudden move across the house in a single step is more likely to unsettle a cat than the same distance covered slowly over a week. Small daily moves, not one big one, is the whole idea behind the step-down approach.
Should I keep both boxes permanently instead of ever removing the old one?
For some cats and some households, yes, and that is a legitimate outcome rather than an unfinished transition. If one cat never fully commits to the new box despite passing every other check, a permanent hybrid setup, one automatic box plus one manual box, kept forever, is a reasonable long-term answer, not a sign that the introduction went wrong somewhere along the way.