I bought myself a book on vaccinations (unfortunately in German and there doesn‘t appear to be an English version, otherwise I‘d have recommended it!
).
As far as I am aware, the lepto a) doesn‘t last long and b) doesn‘t cover all strains. Things like Kennel cough are recommended here and was one of those which caused a „discussion“
with my vet. A lot of the initial vaccinations give protection for years and don‘t need to be refreshed as some vets would have you believe. I also think you need to weigh up the risks, depending on circumstances - country\ city dogs face different risk levels for example.
Just to clarify, (I’m always wary of starting a heated discussion, it IS a controversial subject!
) I‘m not against vaccinations but I don’t think ALL of them are necessary and in my opinion, Titre testing is a great help in helping us decide when and what is necessary (same as test for worms instead of worming willy nilly).