@rugosa So it's like the 3-year rabies vaccine-- exactly the same as the 1-year product but costs more due to the added testing. When Ava was vaccinated last year, her vet didn't have the 3-year DHPP. Hopefully, she won't need to be vaccinated again.
Legally, you don't have to give anything but rabies. And legally it has to say 3 years to be "legal" for 3 yrs. As for the rest, I have every 3 yrs until the dog is old. I give no vaccines after about 7 years old unless there is some new outbreak. Generally, a dog that is healthy is fully immunized by adulthood. If they have autoimmune issues, vaccinations won't help and may make worse. So recommended, don't recommend, when it isn't the law, you get to do what is best for your dogs.