But seriously, things you should ask about the cat before deciding to cat-sit are:
- Is it spayed or neutered? (very important!)
- Is it male or female?
- How old is it? (full-grown cats are usually more self-reliant, less hyper, less bratty & less needy)
- Does it spray? (especially if it is a male cat & is not neutered. Ask it's owner to be honest with you about this.)
- Has it been declawed or had it claws trimmed? If not, does it scatch things? (some cats scratch everything, especially wood & fabric, but many cats do not scratch anything unless they have permission, ie a scratching post)
- Does it have any special diet etc?
- Will it try every chance it gets to escape & get outside?
- Is it a very vocal cat? Some cats, especially certain breeds of cats, are a lot noisier; some are almost silent whereas some will whine & cry constantly if they think they want food, attention, to sleep with you, or to go outside. Siamese are bad for this.
In general, cats are pretty independent & easy to care for as far as animals go. Most don't mind being "babysat" by someone other than their owner, but it does really depend on the cat. I have 2 cats, one would be a joy to cat-sit & not cause any problems or meow at all, the other would probably drive you nuts as he cries loudly a lot, demands a lot of affection, & claws everything in sight, including the curtains & the wallpaper. He is a little brat, but he gets away with it cuz he is the most cuddly affectionate little cat ever & gives hugs & kisses like a person would. Neither of them spray though, & most cats do not spray unless they are an adult male who was not neutered. Cats are very easy to litter box train & I'm sure your friend's cat will not poo or pee or puke elsewhere, unless you feed it something that makes it sick or it eats your garbage or something.
Litter box is easy to clean, just ask them to get the "clumping" "low-odor" cat litter & scoop out the clumps every couple days. This type of cat litter makes a HUGE difference, as it means there is no odor, & makes it much more pleasant to clean the litter box. You don't need to change all the litter, just scoop out the clumps & add a bit of fresh litter on top each time. You only need to empty & change the whole thing about once every week or two. My cats never would go anywhere other than their litter box, even if I forgot to clean it for a month. Also many cats do not get hairballs at all, especially if they have short hair. All cats do shed though, except hairless.
Good luck!