This is a good question - cats don't usually require as much attention as dogs, but they still need daily activation, socialization and companionship. According to the FDA, you should look after your adult cat at least twice a day - giving it cuddles and attention, food and water, and activating it with play. You shouldn't leave a sick or pregnant cat at home for too long, for obvious reasons. Even though cats are more independent, they are still pack animals, and don't do well being alone too much. (If your cat is an outdoor cat, this is particularly important, especially if you live in an area with a lot of wildlife.)
Can I leave my kitten home alone?
A small kitten should not be left alone to begin with, it is still too small for that and can also make up crazy things when no one sees it! If you get a cat, it is therefore best to make sure that someone is at home with the kitten for the time being. It's only when it's a bit older and feels more secure in its new home that you can leave it alone for longer periods. You'll also be able to tell from your cat's personality as it grows how much alone time it needs/wants - all cats are different, and have different needs.
Things to consider when leaving your cat alone
If you're going to leave your cat home alone for long periods of time, it's important that the home environment is stimulating for them. Your home should have plenty of cosy places to sleep, a scratching post, fun toys and preferably an opportunity to climb too! This is of course particularly important for indoor cats who spend all their time indoors, but even cats who are allowed outdoors need a home environment that they can enjoy.