How long does it usually take for one villager to become a master at something. I have two who are master scientists but the builder and farmer are still adept. They all started their various jobs at the same time.
Thanks.

The scientists usually become masters more quickly, because they don't have to travel as far to complete each task. Apart from that factor, how quickly your villagers gain skill depends upon their individual aptitude, game settings, and how you play the game. There are just too many variables to give an exact answer.