For the indoor cat, that means you need to provide it with a litter box and litter. The typical recommendation is one litter box for each cat in your household. If you have one cat, then you need one litter box. If you have three cats, you should have three.
That being said, you may find that your three cats are fine with only two litter boxes. It’s best to rule out a medical issue by taking your cat to the vet and getting a urinalysis to determine whether your cat has a urinary tract infection. If not, then your cat may have a behavioral issue. Then it’s your mission to figure out what is troubling your cat. If you are planning on going on a vacation, you may wish to have a few extras to put out while you’re away. Cats usually want to bury their waste.
Therefore, make sure the sides are deep enough that they can bury their waste without scratching extra up and over the sides of the box. When filling the litter box, make sure that you leave a couple inches of free space at the top for this burying process. You may also want to consider a litter box with a tall back. If you have a kitten, you may need to start with a smaller litter box that they can step into, and then get a deeper one when they are older. Mostly this is your preference. Covers can sometimes help keep odors and litter in, and certainly help block the view of the litter area. However, for larger cats the cover may make it awkward for them to maneuver around and sufficiently bury their waste.
The cover will also need to be removed for you to thoroughly scoop out the used litter. There are lots of pros and cons about self-cleaning litter boxes. The reviews are mixed—some people love them, and some do not. You need to evaluate and decide for yourself. Do consider that it has moving parts, which may not be a good choice for a curious kitten that could hurt itself while trying to play with it when it moves. Also, some cats do not like these because of the moving parts and may refuse to use them. Check the return policy before purchasing one of these, since they are more expensive than a standard one, in case it does not work out for you or your cat.
You may want to consider placing a mat or bathroom rug in front of the litter box to help catch any of the litter that sticks between your cat’s toes and may get tracked around your house. Choose something that is easy to clean the litter out of. This is a slotted large scooper and is sold in the litter section. It is used to scoop out stools or clumped litter while allowing the unused litter to stay in the box. Plastic liners are available and are usually used with non-clumping litter to throw out the entire container after it is thoroughly used. One problem is that cats will scratch a hole for themselves and then scratch again to bury their waste and in this process they frequently scratch through the plastic liner and put a hole through it. This should always be used for kittens because they are curious and like to taste and play with everything.
This type of litter is the easiest litter to use and quickly sticks to feces or absorbs urine to create a clump that can be easily removed with a slatted scoop, while keeping the rest of the unused litter in the box for later use. There are several types including wheat, corn, and clay. Clay is the most common, but it is dusty, heavy to clean and dispose of, scratches surfaces, and is unpleasant to step on. These types of litter readily absorb liquid, and will require a specially slotted scoop to remove the feces, although it does not readily stick to the feces. Cats who are unfamiliar with this type of litter may take a while to adjust. One benefit of this type of litter is that it is not usually tracked around the house from your kitty’s feet.
Your litter box may need to be dumped once a week or more often, depending on how many cats you have. The litter will clog your pipes and cause a back up in your house—you do not want to risk that! Importantly, flushing cat waste is suspected to be linked to the death of sea otters, whales, and porpoises in the US and around the world. If they were in the outside world, they would choose a new spot every time. Inside the home, they do not have that luxury and will be much happier if you are conscientious about cleaning their litter box. If you have multiple cats, then twice a day is necessary to avoid odor and to keep cats healthy. Frequent cleaning will also minimize inappropriate behavior in the house. If your cat has chosen to use the pot of your houseplant, or your bathmat, or another rug, it may be due to an unclean litter box that they don’t want to use. It is not recommended to leave lots of litter boxes out so that you only clean once a week—your cat will not appreciate this and you will have more odors in your house because of it.