You'll need to do it again if you come into contact with questionable animals. Having a sufficiently recent rabies vaccine (and I expect you are well past that window) means you don't need the immunoglobin that non-vaccinated people get at the start of their rabies treatment for a head start on fighting the virus, but you do still need follow-up shots. Though I've heard the immunoglobin is usually the most unpleasant part of the process.