if you're serious.. this is my advice.
Do your research, contact the breeders, see the parent dogs, where they live, their conditions, ask to see their pedigree, ask them about whether they follow the kennel club breeding protocol (not to breed bitches before 2yo, must be heart scored, no more than two litters, two years apart..etc)
If you look at the pedigrees, make sure there are NO REPEATS in at least the last 3 generations. Ask to see the sire and dam health/heart scores. Ask about the kennels average age/life span of their dogs and what they've died of.
Mitral Valve disease and Syringomyelia are the two 'big' issues with Cavs, MVD normally manifests about 5yr of age, but is manageable with drugs.
Make sure you have good healthcare and insurance. Cavs are a breed who benefit from having Titer tests done BEFORE yearly boosters are done.. check their immunity, there is NO need to give boosters for something they still have immunity to. (www.dogsnaturallymagazine.com/titer-testing/)
I'm giving you all this on the fact that my family have always had Cavaliers, we're currently on our 4th.
We lost the first aged 10, to liver failure, but she also had MVD and a lung problem.
The second was 7 when MVD took her, but it was missed by the vet (who we did seek to prosecute.. he missed her heart was twice its normal size)
The third passed away aged nearly 11, he had NO heart murmur, but he did have some serious allergies he was on steroids for and we believe he also had syringomyelia. After losing no2 we did our research and found a kennel with good heart scores, but syringomyelia was a relative unknown and has only come to the forefront in the last few years.
The one we have now cost us A LOT of money, from a show breeder who gives two from every litter to families and only approved us because of our history and knowledge of the breed and its issues. Her dogs have no heart issues and no trace of Syringomyelia. He's only just 15mo but is healthy as a horse!
As to living with them, they can be left for 4-6hours, but i wouldn't do it every day, they crave company, they're the ultimate lap dog and will glue themselves to you. They dont require a lot of exercise, one good walk a day is usually enough. They're wonderful, funny dogs and i love them.
But.. do not even consider it if you cant put in the research to find the right breeder and be prepared to wait for the right dog and make sure you can afford the insurance!