My experience is that a brand new wool garment will stay odour-free very long, but will need washing more often as it gets more use. I think this comes from gradually washing out the lanolin in the wool, which is what actively reduces odour. I usually use jerseys at least three times before washing, for vigorous exercise. Hang them up to dry in between. Just wearing around the house I can get away with a fortnight

But having worn the same base layer for 8 days in the Alps I can attest that yes, wool does get stinky in the end