Cream the margarine and sugar. Then add the eggs, banana, milk, and vanilla. Mix well. Stir in the flour ,soda, and salt by hand. Stir in the pecans last. Pour into a prepared 9x5 loaf pan. Bake for 50 to 60 minutes at 350 degrees. Or pour into 3 or 4 mini loaf pans and it will take around 46 minutes. Cool before slicing.