engineering resources are precious, diverting one team-member to train a new team member is time-consuming and will render two engineers non-productive. Compar

engineering resources are precious, diverting one team-member to train a new team member is time-consuming and will render two engineers non-productive. Compare this to somebody who already knows the technology used, you can explain the basics in a few hours, get him access to the codebase and then answer questions he might have.