I've had foster cats Miss Katie and Kelly for about 9 days now, and they've certainly required more 'care' than other foster cats I've had. Their old age means that they don't always use the litter tray, and they're very messy when they eat and drink. I've forever cleaning up after them. They're also very 'chatty', which again is most probably age-related. Kelly has confirmed kidney failure, and I'm 90% sure that Miss Katie has it too. They're old ladies, it's what happens.
They have this ability to spill each and every bowl of water they drink from, which gets pretty wet.
Miss Katie sleeps next to me each night, whereas Kelly loves her cat cave. They're super annoying but super cute! They don't do much, they sleep, wake up, meow for 15 minutes, eat, pee and sleep again.