It was customary that people whose family had been retainers of the master's family for generations were appointed to the post, and people who belonged to a branch family of the master's family were not appointed in principle.
また主家の譜代家臣が任ぜられるのが通常で、主家の分家などの一門の者が、家老職に就くことは原則的にはなかった。