Although vaccine recommendations are individualized, in general I recommend rabies every three years, DA2PP every three years (on opposite years to lessen antigen numbers), and Lepto yearly as it has increased in prevalence in our area. No one can legitimately dispute the rabies and lepto intervals as both are potentially zoonotic, and if you fail to give those at FDA intervals, kiss your license goodbye if you have an outbreak and human exposure. I believe you will find these to be reasonable recommendations based on our current vaccine knowledge. I am not "hooking" anyone and will gladly run titers for any client trying to extend the DA2PP interval.
Lastly, as I had no clue about the Rabies Challenge Fund, I visited their website. I applaud their efforts in extending the duration of immunity studies for rabies. This is important and potentially beneficial research for sure which may reduce those occasional animals who have severe vaccine side effects. Unfortunately the "facts" are still out and anyone who claims otherwise is just voicing another opinion.