Litter box shopping is one of those categories where the basic, unglamorous spec — size — matters more to whether a cat actually uses it than any added feature.
Size matters more than any feature
A widely cited rule of thumb among veterinarians and behaviorists is that a litter box should be at least as long as a cat's body from nose to base of tail, and ideally longer, giving enough room to turn around, dig, and position comfortably. Many commercially sold litter boxes, especially covered ones, are smaller than this guideline for an average adult cat. A box that's too small is one of the more common, fixable reasons a cat avoids using it or eliminates outside the box — before assuming a behavioral or health problem, checking that the box itself is actually large enough is worth doing first.
Covered vs. uncovered
Covered boxes contain litter scatter and odor better and offer more privacy, which some cats prefer. Others are put off by the more enclosed space, especially if it traps odor more noticeably inside, or feel more vulnerable without a full view of their surroundings while using it. There's genuine individual variation between cats here — neither style is universally better, and if a household is switching styles, it's worth watching to confirm the cat actually adapts to and uses the new box.
Self-cleaning boxes trade convenience for mechanical complexity
Automatic, self-cleaning litter boxes reduce daily scooping significantly, which is a real convenience — but they're mechanically more complex, cost more upfront, and can occasionally malfunction or startle a cat with movement or noise during operation, particularly right after installation before a cat gets used to it. They also generally still need regular manual cleaning and maintenance of their own, just less frequently than a fully manual box.
More boxes than cats is a real rule, not a suggestion
A commonly recommended guideline is one litter box per cat, plus one extra — so a household with two cats would ideally have three boxes, placed in different locations rather than clustered together. This isn't just about capacity; cats can be particular about resource access and location, and insufficient or poorly placed litter boxes are a well-documented contributor to litter box avoidance in multi-cat households specifically.
The one thing people forget
Scoop daily regardless of the box type, including self-cleaning models. Even boxes marketed as reducing maintenance still benefit from a quick daily check — cats are often sensitive to a soiled box and may avoid a box that's noticeably dirty even between a self-cleaning cycle.