Much has been made of the euphoria surrounding the Ardern Administration and its similarity to the adulation that followed David Lange into office - just four years her senior at the time - when he came to power in 1984.

There is an air of excitement around parliament, with the new Labour-led government promising to be one of change. And that was the case with the Lange administration, essentially because things had to change. Under the draconian rule of Rob Muldoon, the economy was in an icebox.

Everything was frozen, from wages to prices, from mortgage interest rates to welfare benefits for sheep. The same can't be said of the present government's inheritance.

When Lange swept to power the cabinet secretary of the time, an office that assures the utmost of discretion, confided to me that he was a breath of fresh air.

They weren't just economic reformers with Rogernomics, they were social radicals, giving the bird to Uncle Sam with the anti nuclear legislation and legalising homosexuality, to name just a few of the many changes that were ferried in.

But Jacinda Ardern's coming off a very different base and her 100 Day plan is mild by comparison. Free tertiary education for the first year, banning foreign buyers for existing homes, undoing National's tax cuts and replacing them with their families package, and increasing the minimum wage is hardly on the scale of the Lange juggernaut.

She'll be wanting to emulate Helen Clark anyway, rather than Lange, given that his was the first Labour government since the war years to get a second consecutive term under the old First Past the Post system. With MMP it's an even harder task to keep things on track. The wheels well and truly came off the tracks with Lange whose public appeal was private purgatory for those around him, with his government disintegrating, delivering three Prime Ministers in his last term.

For Ardern, the biggest challenge will be keeping her disparate coalition cobbers in check.

Ardern would do well to pinch herself in the coming weeks to remind herself that the excitement she's created as the new, fresh-faced leader doesn't last forever.

She was no doubt reflecting as she moved on to the Beehive's ninth floor yesterday, that the last time she was there was as a civvy street underling to Clark.

Passing each other on the bridge between the Beehive and the old Parliamentary Buildings, the appearance of Bill English heading over to the opposition offices should have been a reminder to Ardern that his is the fate of all Prime Ministers it's only a matter of time.

It's what she manages to do with that time that she'll be remembered for.