The confusion here is understandable, because numerology has more than one number and only some of them are annual by design. The life path number draws entirely from your birth date — a fact that doesn't change no matter how many years pass.
What does change is the personal year number, which folds your birth month and day together with the current calendar year. That one genuinely resets on a yearly cycle, and it's almost certainly the concept people are half-remembering when they ask this question.