A walk a day is sufficient. They make good apartment dwellers but should never be taken out of a fenced area without a leash. Greyhounds can be very cat-friendly. As with all strange animals being introduced to each other, you must use caution. Most greyhounds who are adopted by families with cats, end up as the cat's dearest friend.
Greyhounds are usually very healthy with a life expectancy the same as that of other breeds.
It makes a difference in the amounts of medication that can be given a greyhound. All greyhounds must be spayed or neutered.