Answer: Although there are some people who believe the answer should always be no, it really depends on your individual circumstance. It would be reasonable to keep a cat if you are absent only during the normal working day and are home in the evening and at weekends, and provide that the cat is able to enter and leave the premises (through a cat door) when you are not around. However if you are away from home more frequently then that, it is doubtful whether the arrangement is fair to the cat. Of course, you might arrange for neighbor to feed the cat when you are away, but usually there is no permanency about such arrangements. If you really care about the cat and put its interests first, which you should, it is clearly a very poor home at you are offering.
If you live in an apartment, it may provide impossible to let the cat have access to outdoors. With a ground floor or basement apartment the situation is obviously different. If you live in an apartment above that level, it may even be possible for a cat to reach the ground via floors or a cat ladder, which will not support the weight of any heavier animal, including potential housebreakers. But always ensure that the cat has free access back into the premises and to its bed. Make sure too that fresh water is always available when no-one is at home.
Since a kitten would require feeding three or four times a day and house training, it would be better for single working people to take in an older cat, even through it will almost certainly take longer for it to adapt to its new home. Bear in mind that you could encounter problems when you want to go on holiday, or if either you are the cat is taken ill- especially if you have to go into hospital.
If you really can’t arrange all time, then you shouldn’t have a cat. Some less demanding creature such as a budgerigar, a golden hamster or a goldfish might be suitable, but even these will require regular cleaning even through they do allow more flexibility, in feeding for example. Any cat that cannot be let free outdoors must be provide with a litter try and with regular exercise, perhaps by providing an outdoor run.