Litter trays are essential for inside only cats but why should they be provided for inside/outside cats ?
Reasons to provide litter trays for inside/outside cats :-
Consideration of neighbours, by providing inside litter trays your cats are not fouling in other peoples gardens.
Allowing elderly and sick cats the option of inside litter tray will reduce further illness or discomfort of dragging themselves outside to toilet.
Being able to monitor your cats toileting habits will increase the chances of spotting illness earlier and early treatment is more likely to result in recovery from serious problems like UTI infections.
Always provide a litter tray when your cat is restricted to the house.
The standard rule for inside cats is one litter tray per cat plus one extra. Two cats need three trays and Three cats need four trays etc.
It is important that the litter trays are placed in the right location or else the cat will not use them. Trays should be placed in quiet areas where people and cats will not bother the cat using the litter tray, hence a corner of a room is better than a corridor.
Trays can be shallow boxes, deep boxes or have covered lids. The type of litter tray used depends on space available and the cats preferences. Covered litter trays are particularly good at cutting down on bad smells.

Whichever type you choose ensure that the cat can comfortably fit in the tray and that if the box is covered that it is tall enough for your cat to stand up.
There is a wide range of litter available in the shops. As every cat has their own preferences, finding the right cat litter is often a case of trial and error. Check with the shelter or home that adopted out your cat and ask what they use, as it is always worth starting with a brand that your cat is used too. Just remember NEVER use clumping litter with kittens. Kittens sample litter and clumping litter can swell in the kittens stomach causing problems.
Make sure that the litter tray is scooped daily and weekly emptied out the tray and wash properly. Dilute a small amount of bleach with hot water to clean the litter trays, then rinse well with hot water and let them drip dry. Never use a cleaner which contains ammonia to clean a litter tray, as your cat's would not use that tray again. Replace Litter Trays regularly, as scratches in the plastic are hard to keep clean, we replace all trays every six months.