How we judge and rank

A verdict is only useful if you know what produced it. Here is ours.

Where a verdict comes from

Every judgement on this site is built the same way, and it is checkable line by line: we read the specifications, the manuals and the standards that apply to the machine, we weigh what long-term owners consistently report about it, and we name the source of every figure we publish.

That last rule is the one that does the work. A number with a source can be argued with; a number without one is decoration. Where a figure exists in a manual and contradicts the marketing, we quote the manual. Where no reliable figure exists at all, the page says so and leaves the field empty rather than filling it with something plausible.

What we weigh

We rank on the specifications that decide the job and the ones that decide how long a machine keeps doing it. In practice that means five things:

• The number that governs the machine. The minimum weight a litter box will detect, the kibble size a feeder jams on, the chip standards a door reads, the update interval a tracker holds at that battery life. Where a maker publishes a headline figure without the one that qualifies it, we say so rather than repeating it.
• The thing the animal decides. Noise on a grooming vacuum, the smell of a scented refill, the entry height of a box, the swing weight of a flap. Every category has one detail that decides whether the appliance is used or avoided, and that is the one we describe.
• What the machine can get wrong. What happens to a cat under the sensor threshold, how a dryer limits its heat, whether a collar releases under load, what a jammed feeder does at the next scheduled meal. This is weighted more heavily here than on most sites, deliberately.
• Consumables and serviceability. What litter, cassettes, filters, blades and seals cost over a year; whether parts are sold separately; whether the refills are proprietary or generic. This is why a machine that performs slightly worse sometimes outranks one that performs better.
• Availability where you are. We verify each product reference market by market. A machine that is excellent but not distributed in your country is not a recommendation we can make to you.

Where the evidence comes from

Three sources, weighted differently and always named. Manufacturer specifications and manuals, cited as such rather than repeated as fact — they are reliable for dimensions and unreliable for performance. Published standards and independent measurement where they exist. And the weight of long-term owner reports, which is the only practical source for the question that matters most: what is this machine like in year ten, after the warranty and after the honeymoon?

Where a claim rests on one source rather than three, the page says so. Where we could not source a figure at all, the field is left empty and the gap is stated. We never fill one in by inference.

What the ordering means

We publish no scores. There is no number out of ten on this site, and there never has been — a single figure would have to compare a €500 litter box with a bag of guide combs, and it cannot. What we publish instead is an order: within a category, the sequence is deliberate, and the reasons for it are in the text.

Hubs are sorted by price tier — entry, mid, then top — because a hub should read like a budget ladder, not a list with the most expensive machine nailed to the top.

The biases we designed against

Affiliate sites drift towards expensive products, towards whatever is newest, and towards whatever converts. Our defence is structural rather than a promise: no ranking on this site has ever been reordered because of what a product pays, several pages recommend a €6 seal instead of a new machine, and no product has ever been placed in exchange for anything.

The one bias we cannot remove is availability. We cover what is genuinely purchasable across Amazon's US, UK, German, French, Italian and Spanish stores, which means excellent machinery sold only through specialist dealers — a good deal of the serious European market — is under-represented here. Where that matters to the recommendation, the page says so.

Safety is not a section, it is a constraint

These machines move on their own around an animal that cannot read the manual. A litter box cycles on a weight sensor with a published minimum, and an animal under it is one the machine does not know is there. A dryer puts heat near skin. A collar that does not release under load is a hazard rather than a feature. No page here ranks a device higher for letting a safety delay be shortened, and no procedure on this site replaces the manufacturer's instructions for your specific machine. Where a technique is commonly done unsafely, we describe the safe version or we do not describe it at all.

Where this site stops

We write about equipment. We do not diagnose, we do not prescribe diets, and we do not interpret what a scale, a camera or a feeder tells you about an animal's health — that reading belongs to a vet who can examine the animal. Pages that touch the boundary say so in the text rather than in a disclaimer at the bottom.