Having an indoor cat does not mean your cat will be unhappy. If they have never known the outdoors or have had an accident, making it so they cannot go outdoors, then they can be content to stay inside. However there are a few things that need to be taken into account. These are keeping your house clean for yourself and your cats... as cats are very hygienic, and making sure they are happy and do not get bored... which can result in your home, for example furniture, getting wrecked.
Of course your cat will need a litter tray. If there is more than one cat living in the household it is a good idea to buy more than one litter tray as cats hate going to the toilet where others have... and I do not blame them! There are different litter trays that can be purchased but the best ones are the ones that have a hood over them like a cat carrier as then the cats get to go to the toilet in peace, it decreases the smell in the room and when they flick the litter it does not make a mess on the floor as it stays inside.
Your cat or cats will also need space and plenty of it so access to a number of rooms is vital. Without space they cannot exercise so weight gain is inevitable as well as boredom from having no space to have a run around or be nosey around the house. They will become withdrawn and your once happy, cuddly cat will not want to engage with you. If there is a specific room in the house that you do not want them in... just shut the door. With the space around the house they have they should also be given access to a few different beds. One up high so they can see outside and one in a corner so they can curl up and hide away to sleep gives them a choice of what mood they are in. You can also get radiator beds which just hook on your radiator to give your cat an extra warm bed in the winter.
If you do not want your furniture ruined a scratching post is a must. Depending on how many cats you have usually depends on the size or how many you have but it gives them something to sharpen their claws on and mark their territory... which cats like to do a lot. As well as scratching posts some toys would keep your furry friend active as well, especially if you spend half the day out the house because of work.
All these things will help to ensure you have a very happy cat and a very happy human.
