Ok, for what it's worth, here is my take on this....
I spoke with my vet about this, and also with a breeder, and basically there is some discrepancy as to whether titers are sufficient to indicate immunity. The American Vet Association is supposedly currently reviewing the data regarding immunity conferred by memory cells as opposed to immunoglobin levels, and what this implicates for the titers that vets currently perform. HOWEVER, there is a general consensus that american dogs are WAAAAAY over-vaccinated. Many Havanese breeders recommend following the Dr. Jean Dodd vaccine protocol, which indicates going through the complete round of puppy vaccinations (minus the corona virus vaccine and definitely no Lyme), and then having titers performed yearly.
Currently, it is cheaper to vaccinate every year than to titer (@30$ per shot as opposed to 70$ per titer), but it is somewhat uncertain as to what the titer results represent in terms of immunity conferred. So, what both my vet (Recommeded vet of the Delaware Valley Havanese Club) and one of my breeders believe is that currently titering after the 1 year vaccines is the best substitute for annual shots. There are experiments underway to test this, but you wouldn't vaccinate a human child annually, so many medical experts believe you shouldn't do that to a dog either. They are also testing to see if the rabies vaccine really needs to be delivered every 3 years or if 2 doses are sufficient to confer lifelong immunity to our Havs. I speak to them both often, if I hear more on the topic, I will let you know.
IMHO, as someone who has worked as a scientist or engineer in both pharmacology and oncology, the fewer vaccines that you deliver annually to your dog, the better. I think that for now, if I were you, just tell your vet that you follow the Dr Jean Dodd protocol for vaccination, and many vets will think that is sufficient. I could try to find an online copy of the protocol.
SOrry this is so long and serious, I am in work mode right now