I began wearing hats as a young lawyer because it helped me to establish my professional identity. Before that, whenever I was at a meeting, someone would ask me to get coffee.
I got a tiny part in a play, auditioned for another one and got that as well. Not only that, the first finished on the Saturday and the other started on the Monday which is like an actor's dream!
A large wildlife book, start to finish, could take one to two years, but then I would expect to get several good (nature) magazine features off the back of this, plus of course a lot of stock.