Applicants for the job of prime minister need to have experience, deliver on commitments and care about people, says a recruitment specialist.
It's just like applying for any other leadership role, said managing director at Hays specialist recruitment Jason Walker.
Three candidates have put their hands up to fill John Key's shoes - Bill English, Jonathan Coleman and Judith Collins.
Walker told Newstalk ZB's Mike Hosking a good leader needs to be credible.
"As soon as you see this individual, or hear about them, you've got to ask whether they're credible enough to get the job done."
He said competence is also an important quality of a good leader.
"You've got to have the ability, experience and capability to execute and deliver on the commitments and objectives of the company."
Finally, he said a good leader has to be caring and authentic.
"You need to be passionate and engaged about the organisation and the people who work for you."
Mr Walker said what makes someone exceptional is their ability to bring those elements together.
"It is unique to get someone with all those qualities... and that's where the magic is."
He said that's something John Key was able to do.