Prime Minister Jacinda Ardern raised the question of succession planning at her reshuffle this week, signalling she would do a further reshuffle next year.
Ardern is not outwardly planning her own succession, but she is trying to make sure the party she leads is in a strong position when she's no longer around to lead it.
She'll want to make sure some tired older ministers move on, while some solid, front bench and middle-ranking ministers are ready to pick up the responsibilities of leadership, either in government or opposition.
It's often said that if Ardern pulls a Key and bows out in the middle of next term, her Deputy Prime Minister Grant Robertson is the obvious successor. Labour's new leadership election rules, giving caucus power to elect a leader if two-thirds agree, make this even more likely.
But if Labour loses, either next year or afterwards, both Ardern and Robertson will almost certainly retire together (Ardern has previously confirmed she would bow out if she lost an election).
Ministers like Chris Hipkins and Megan Woods will need to decide whether they too bow out, or stay on to steady the ship through a difficult time in opposition. Ardern did the right thing on Monday, shining the spotlight on these two ministers as well as more junior members of her Cabinet clearly destined for high rankings like Kiri Allan and Michael Wood.
Ardern is wisely creating depth in her ranks that will outlast her own leadership. She's now got to have difficult talks with senior Cabinet ministers, perhaps convincing some to retire in order to make room for talented but untested MPs from the classes of 2017 and 2020.
Labour did the right thing in 2020, using the opportunity of the party's popularity and polling to select and later win seats for a crop of talented MPs. The last thing Ardern wants is to see all that work wiped out by a disappointing result in 2023. Even if Labour wins, it will almost certainly shed MPs.
Ardern's reshuffle has so far been examined for what it means to Labour. That's understandable, but the reshuffle also poses questions of National, which has challenging caucus problems of its own.
Like most parties in the MMP era, National has used its party list to bring essential diversity to Parliament. The blunt realities of First Past the Past contests in electorates have tended to favour male candidates from Pākehā backgrounds.
In 2017, the bottom of National's list brought in candidates representing many migrant communities traditionally lacking in Parliament. However, they failed to advance up the list, often because the top of the list lacked balance between social liberals and conservatives. The wipeout of 2020 means these MPs have now gone, and National is facing serious questions about how well its caucus represents the community it seeks to serve.
Labour has done a good job of moving beyond simply using the list to diversify caucus. The much-derided 'man ban' means women are selected in winnable seats. Labour's 2020 caucus includes more women representing electorate seats than men.
National is quite different. It has 23 MPs representing electorates in its caucus, 16 of whom are men and just seven of whom are women.
Fixing this is no easy feat. One of the much-touted benefits of being a National Party member is the fact that local members have a strong say in who gets selected as their electorate candidate. As we saw in 2020, meddling by the board and National head office in candidate selections is frowned upon. That's no bad thing; local democracy is healthy in a party after all.
The problem is that this process often leads to what is playing out in Tauranga right now, where despite clear national (lower case 'N') pressure on National to diversify, local members opted to select Sam Uffindell, a man who, though apparently talented and clearly well-credentialled, does little to solve the caucus's diversity problems.
The National board, including Christopher Luxon (who sits on the board), needs to find a way to reconcile these two countervailing trends: He'll want to preserve local democracy in the party (it's important to keep members happy - they donate money and knock on doors), but he needs to boost caucus diversity too. It cannot be the case that one of these trends perpetually cancels the other out.
Labour has slowly changed this and now has more women representing electorates in its caucus than men. National may always be something of a laggard in this respect. It is a conservative party after all, and current polling shows that voters aren't too bothered by what they see - indeed, they appear to rather like it.
However, the revolt of women and cities away from the Liberal Party in Australia shows what happens when a party does not evolve with its country.
National has not yet been deserted by women - the most recent Taxpayers' Union-Curia poll showed 34.3 per cent of women supported National versus 37.5 per cent supporting Labour, but it's not difficult to see women abandoning National like they did the Liberal Party if it fails to represent them in caucus, or in politics more generally.
Nearly a year out from the 2023 election, National's current polling suggests it could gain as many as 18 seats. The party needs to do the legwork now to ensure those 18 MPs aren't the liabilities previous selections have been - and that it includes possible ministers and leaders who will inherit the party after Luxon eventually bows out.
Opportunities like this don't come along often.