When is the best time to give annual shots?

[GoldenTreePackGoats]

I vaccinate my at the end of September or early October. Like what was stated before I have 2 siblings that get an abscess every time they get vaccinated. The vet I work with for my goats care said that vaccinating every other year would be fine. I will say I worked at an animal hospital as a vet tech and some people are anti-vax, rabies is required for cats and dogs so there is an option the county allows to check blood titers for a few hundred dollars, and dogs/cats that hadn't been boostered more than twice had adequate levels even after 7 years. Also 3 veterinarians haven't had to booster their rabies vaccine in 20+ years. The reason vaccines are suggested so frequently is to err on the side of caution since there aren't any studies to back it up.