In the leadup to the 2014 election, the NZ Herald did an article on the toll the stress of the job took on the Prime Minister.
It was indelicately headlined "The ageing of John Key" and accompanied by an equally indelicate photo essay. He was a good sport about it.
He even did an interview for it – pointing to the 100-hour weeks and the similar effect on then US President Barack Obama. He later told me his wife, Bronagh, put it on their fridge to keep him humble.
In that article, Key said he was oozing energy and when the day came he was no longer excited about the job he would walk away.
That day came two years later, and despite the warning, Key's retirement took most people by surprise.
A similar piece would not be done on Prime Minister Jacinda Ardern. Yes, that may be a double standard but I do not care - we would be crucified.
However, eventually Labour too will have to confront the reality of a future without Ardern.
While everybody is wondering how long Judith Collins will rule the National Party and speculating on her successors, nobody is really thinking about how long Ardern will rule the Labour Party – or who would succeed her.
This is not motivated by any inside information or speculation that the Prime Minister is planning to stand down and work at the UN or whatever the latest rumour is.
I have no idea when that might be or what Ardern might end up doing.
However, Ardern will never be rolled as leader.
She will leave one of two ways: either she will do a Key and leave while still Prime Minister, or she will lose an election. She has already said she would resign if she lost an election.
The Labour Party is moving now to change its rules to cater for the possibility that Ardern does follow the lead of Key.
It might not surprise people if she eventually did that, but it would surprise people if she did it this term.
The rule change would allow caucus to bypass a vote of party members and union affiliates and elect a new leader themselves. That could happen if more than two thirds of the caucus supported that person.
There are already jokes (mine) about the new clause being called the Grant Robertson Clause.
That is because if Ardern did step aside while still PM, it is almost certain she would want the job to go to Robertson. That would also make it almost certain Robertson would get the caucus vote required.
That is because of the same reasons Key wanted English to take over from him: because the public trusted him. Robertson is the one most likely to be able to keep things on an even keel without Ardern – and to hold up the vote for Labour.
Labour's rules needed to make any such transition easier.
Its current process is protracted, cumbersome and unpredictable. Without a quick, clean leadership change, there is the prospect of the country sitting and waiting for weeks on end while Prime Minister wannabes strut their stuff to party members and trade union affiliates – and then those members and unions chose the next Prime Minister.
Until now, the only way to get out of process and let caucus alone elect a leader was in the three months prior to an election – as happened with Ardern in 2017.
The changes will be voted on in November at the party's conference.
It is being done now because the best time to make such changes is when an incumbent leader is safe and the party is stable.
The best time to do it is when nobody else is being talked about as a leader.
But that is also a problem for Labour, and a critical question it will eventually have to face.
Labour has a strong leader now. But will it too face another carousel of changing leaders when it goes back into Opposition?
The Robertson option is far less likely if Ardern leaves after losing an election. At the moment, that does not seem likely but Ardern herself has seen how public sentiment can turn quickly.
Robertson would likely want to go with her, rather than back into Opposition. That was what the late Sir Michael Cullen did after the Clark government ended.
Robertson has ruled out another go at the leadership after being twice thwarted by Labour's current leadership processes.
It remains possible Robertson could be prevailed upon to stay on anyway to hold the caucus together as it adjusted to the difficult life of opposition. That was what Phil Goff did in 2008 after Clark.
However, history has not been kind on first term opposition leaders.
When a leader is as commanding as Key or Ardern, little attention is paid to thinking about who might come after.
There are two approaches.
One is the senior caretaker leader Labour tried with Goff. The other is to move straight to the next generation of leadership, as National did with Simon Bridges after 2017.
Ask Labour insiders who might take over after a Labour loss and there are blank faces.
Some come up with names for the future: Kiri Allan or Kieran McAnulty, maybe Michael Wood, who has strong support among the Auckland members and unions.
But there is no real consensus around any particular person.
As for the more distant future, sometimes leaders are pointed out early and sometimes they eventually come into focus.
In National's intake of five new MPs, Christopher Luxon was dubbed a leadership prospect very early on.
In Labour's intake of 23 new MPs, not a single name has been pointed to as yet.