my parents have 3 cavaliers at the moment - they have had 5 others before now. 1st one was tricolour, lived to 14, no problems except blind in one eye after an attack by a german shepherd.
2nd lived to 16, no problems.
3rd we had for 2 weeks - he was a rehomed dog, and had such behavioural problems we couldn't keep him. he was rehomed with a family with no other dogs and thrived.
4th dog lived to 14, had heart problems, and nearly died when he was 11 due to incompetent vet deciding to operate on him when he had a gut upset. also turned out to be epileptic after several litters had been bred from him.
5th dog broke his shoulder badly as a pup due to being very silly. had arthritis as a result in the mended shoulder. lived to 15, but last year of his life he was a shambles and drugged up to the eyeballs.
current ones are 14, and 2 4 year olds. one of the 4 year olds is the great grandson of dog 4, and may have mild epilepsy. the 14 year old is decrepit and going deaf, but still enjoys his walks! the 4 year olds are total loons, but very cute and funny! one is being used as a stud dog, and the breeder sold him to my parents on the understanding she could use him occasionally.
Oh, and my grandmother is on to her 3rd cavalier, and he's 14 and still going strong.
so in other words, out of 9 dogs, they have all lived long lives so far, and although they have some problems, I think we have been lucky with good breeders (dogs 4, 6, 7 & 8 all from same breeder).
my parents and grandmother all keep the dogs quite slim though - not walking footstools like a lot of cavaliers you see.
I miss my cavs though, they are wonderful dogs.