It is sometimes advantageous to hire from within because it is less costly, and helps maintain employee morale.
When you hire from within your company for a promotion or different position, it is often less costly because the employees are already trained in how the organization works. They won't have to spend money on her hirer information and ground level training. It also keeps the employees happy because they are able to see that there is potential for growth and by working hard in their current position they have a way to change positions and receive promotions.