If I am making one item, I either dip it or brush it on the finish. If I am making a lot of something, like toy trucks, for example, I will break out the airbrush. Some things, like wheels, always get done with a brush since getting finished in the hole causes problems when gluing.
I started this because a potential customer wants a natural oil finish. There is only one: tung oil. My definition of natural is that you put it in a press and squeeze it, and oil comes out. There are other oils that fit this definition, but they all will turn rancid.