I have my dogs blood work done once a year, and always before dentals or any surgery.. My Flumpy had a problem with his spleen.. My vet was just getting ready for the surgery when she reviewed his blood work.. He was a bleeder and had she not done the bloodwork, and had gone ahead with the surgery, he would have bled to death.. We still weren't able to save him in the long run, but with chemo we were able to keep him for another six months that we wouldn't have had if I had chosen to skip that very important step.. It may seem like it isn't necessary, but it really is VERY important..