There is a very wide selection of cat litter available on the market these days, each with its own advantages and disadvantages, and it is important to consider which type will best suit your arrangements and the needs of your cat. Commercial cat litter has only been available in Britain since the late 1940s - before then, most cats used to go in the garden (or the neighbour's garden!) and very few people had litter trays indoors. Those that had them often used an old wooden seed tray, or similar (usually referred to as a 'dirt box'), filled with sand or earth from the garden, that had little absorbency and plenty of scope for unpleasant smells!
There are three main types of cat litter available, with a good range of brands and variations for each one. New varieties appear from time to time, all claiming to be a new revolutionary method, but many do not survive long in a very competitive market. It usually works out cheaper overall to purchase the largest sizes available, and you will often get the best deals by buying at a cat show where the traders are selling so much stock on the day that there are usually special show offers. But it's definitely worth shopping around for cat litter, both at large pet stores and online, as prices can vary enormously.
Clumping litter e.g. grey Fuller's Earth type - this usually includes sodium bentonite, a type of clay that expands and forms hard clumps when wet.
Non-Clumping litter - usually small pellets made from compressed sawdust or recycled newspaper
Silica gel litter - the newest variety, sometimes known as 'crystal litter' - a porous sodium silicate in the form of clear granular particles
Whichever cat litter you choose, it is essential to clean your litter trays and refresh the litter regularly (particularly with Fuller's earth and woodchip/newspaper pellets) to keep the area clean and your house smelling fresh. Cats do not like dirty litter trays, and will often use an alternative area, such as the floor, if the tray is not up to standard in their eyes! Although you can buy litter 'sprays' to banish any surrounding odours, all this is doing is masking the smell rather than getting rid of the problem.
There are a variety of litter tray designs on the market, and you may need to see which one your cat has a preference for! Some cats like trays with hoods or lids, which are effective in minimising the spread of odours, especially if you are out all day - nobody likes being hit with the smell of a litter tray that needs changing as soon as they come in through the front door! Other cats won't use enclosed trays at all, and you may need to experiment a bit when you first get your cat. Small kittens need a low tray that they can get in and out of easily, and can only progress to the larger more elaborate designs as they grow larger.
Litter trays often used to be positioned in the kitchen, but it's better to put them in the utility room or maybe the conservatory if you have one, as there will be inevitable strong smells from time to time, but the key to reducing long lasting smells is to check the trays regular and clean them thoroughly at least twice a day. It is usually advisable to have a large litter tray (approx. 35 cm x 50 cm) for every 2-3 cats.