Cat's Best or Catsan cat litter?

Which to buy

Pick Cat's Best for an adult cat when you want to lift out wet clumps and top up, rather than empty the whole tray every week. Cat's Best says the litter can stay in the tray for up to 5 weeks before a full change, and its 20L bag weighs 8.6kg against 10kg for Catsan's.

Pick Catsan for a kitten. Catsan says Hygiene Plus suits kittens, and that non-clumping litter matters for kittens under 12 months because they may eat litter. Cats Protection gives the same advice: avoid clumping litter for kittens, as swallowed clumps could cause a blockage.

Pick Catsan too if a weekly routine suits you: lift out the solids each day, then empty, clean and refill the tray once a week, as Catsan suggests.

Price per litre is not price per month

The routine is where the litres go. Catsan's tray is emptied and refilled about once a week; with Cat's Best you take out only the wet clumps and top up, and its maker says a full change can wait up to 5 weeks. Cats Protection adds that non-clumping litter may need replacing more often, since urine is harder to remove.

On the makers' own figures a bag of Cat's Best can last longer than a bag of Catsan the same size, so compare the cost of a month, not a litre. Work it out from your tray: the litres it takes to fill to the maker's depth, times the full changes in a month.

Switching and the bin

Change litter slowly. Cats Protection suggests mixing a little of the new litter into the old and raising the share over at least a week, rather than swapping overnight.

Both makers say used litter can go in the household waste. Cat's Best says single clumps can go down the toilet where local rules allow; Catsan advises against flushing any litter, saying it wastes water and puts a strain on waste water treatment.