We see our prime ministers almost every day. We are all-too familiar with their voices, their mannerisms, their favourite sayings. And then all of a sudden, one day, they are gone from national life. So when they, per chance, pop up again, it is a cardigan experience. A bit like going back in time.

For Julia Gillard, however, it is unlikely that her appearance before the royal commission this week was a comforting one.

It came after some two decades of questions about what she knew of a "slush fund" set up by an ex-boyfriend in the 1990s and if any money from the fund was used to renovate her then house. It also followed years of the Coalition banging on about general union dodginess, and its targeted pursuit of Gillard when she was prime minister (remember Julie Bishop's paper-waggling attack?) over the Australian Workers Union Workplace Reform Association. Now they finally had the former PM in the chair at a royal commission.

On Wednesday in Sydney, Gillard was questioned for four hours with a one-hour break in the middle for lunch. She was taken through tabs and sections and sub-paragraphs of documents. She was asked about her legal career in the 1980s, her knowledge of West Australian and Victorian laws for the incorporation of associations, the file she didn't open on the work she did for her then boyfriend and his union sidekick and whether she had "invoices" or "receipts" for the work tradespeople did on her Melbourne home. And so on and on and on.

By the time Gillard was excused, at about 3.30pm, the biggest revelation was that when the young lawyer was away on holiday in Queensland, her then boyf had demolished the bathroom, providing the catalyst for her home renovations. Even to this day, you could tell Gillard was severely unimpressed. As she dryly observed: "I'd been talking about getting the renovations done for quite a long period of time. Bruce Wilson obviously thought I should get on with it and created circumstances where I had to get on with it."

What a keeper he must have seemed.

As has already been observed this week, the hours of royal commission questioning failed to produce a gun, smoking or otherwise. Again, what we were left with was the sense that in the 1990s, Gillard associated with some pretty questionable types. She cut some corners with her filing. And she had a stressy home renovation.

In the wake of the appearance, some commentators have suggested that we now "move on" from the saga – or at least from Gillard's involvement in it. She's faced so many questions over so many years. She has always denied any wrongdoing. There is no hard evidence to suggest otherwise. We have all had dating experiences that should have been avoided. What more is there to say?

Others, however, have argued that "ticklish questions remain swirling" around Gillard – that she has avoided interrogation from those with "deep knowledge" of the matter. She has "stonewalled". They pounced on Gillard's admission that if she got to "do the whole thing again", she would "do things differently".

(If you had faced 20 years of public cross-examination about your ex-boyfriend, wouldn't you?)

Either way, we are getting to the point where shoulders could be forgiven for shrugging. None of the AWU saga relates to her time as prime minister. Or even her time as an MP.

The timing of Gillard's appearance on Wednesday was poetic for a couple of reasons. Not only was it almost a year to the day since her great political foe, Tony Abbott, won the election, it was just weeks away from the release of her memoirs. In My Story, Gillard will paint a much rosier picture of herself and her career – as the promo goes: "I was Prime Minister for three years and three days. Three years and three days of resilience. Three years and three days of changing the nation".

It will be her official bid for what her legacy should be, carving it in her own image, away from Kevin Rudd and from Wilson.

In the predictable clamour to review the book, it is worth noting that legacies are not settled so soon after the event. John Howard was persona non grata for a spell, after he not only lost the election but his seat in 2007. Now he is trotted out by both sides of politics as an example of good government.

Gillard does not have a time machine, but she may yet enjoy the benefit of other people's hindsight.

Judith Ireland is a Fairfax journalist.