I believe in only Parvo/distemper as a puppy (rabies at the appropriate age) and then I only booster for rabies. There are plenty of studies done showing that vaccines last for seven years or even longer. Most, if not all, vets now come out of vet school doing every three year shots. I like to raise my dog's natural immunity with a good diet and minimal use of heartworm medicine and no harmful insecticides for fleas/ticks. I will eventually titer, but haven't had the need to yet, as my training facilities implement a holistic approach, along with my awesome vet whom I love.