While others played T20 leagues around the world, or club or county cricket in England, Mills stayed home. He has family commitments but saw plenty of trainer Chris Donaldson. That, and trips to the Mount to bowl on grass pitches over the past seven weeks, have kept him in decent nick.
Unless things go badly awry in the next three months, expect Mills to be in the final Cup 15.
After South Africa's three-game visit this month, there are games in the United Arab Emirates, both against Pakistan and a series of New Zealand A fixtures against the four associate member nations coming to the World Cup. Sri Lanka have seven ODIs in January; Pakistan a further two.
Mills' numbers stack up well, over 13 years, dating back to his ODI debut in Sharjah against Pakistan in 2001.
"Form between now and then [the naming of the Cup squad in January] will dictate whether you make the final 15, so hopefully I can keep playing well over the next few games," Mills said.
Only Dan Vettori has more ODI wickets for New Zealand than Mills, who has been a consistently impressive performer down the years. He also possesses a pile of accumulated cricket wisdom.
He didn't say so but he'll be keen to make, and complete, a World Cup.
In 2003, he played one game in South Africa; missed 2007 altogether and played just three games in 2011 before being injured. The fact it's being held in his country's back yard adds to the sense of thrill.
Just don't ask him about the R word.
"Since I turned 30 [he's 35 now] I've been asked when I'm going to retire. All these comments were coming my way so I started thinking maybe I should be stopping after the World Cup," he said.
"It does have a fairytale ending, but if I'm playing well, the body is good and form dictates I can still compete at this level, I think maybe I can keep going.
"A lot of players have gone on to their late thirties. We'll see how it's going. I have to pull up stumps at some stage and it might be a good time."
Talk Cup favourites and Mills reckons - excluding New Zealand - two countries stand out.
"I think South Africa and Australia are going to be really tough to beat. Subcontinental teams, they're not going to struggle but conditions here and in Australia are going to be bouncy wickets, not so conducive to spin, so that's not going to be as prominent as in previous World Cups on the subcontinent."
Mills rates highly both teams' pace attacks, especially in Australasian conditions, and both, particularly South Africa, have well-balanced batting lineups.
"I'm not saying a team like [defending champions] India can't win it, but I think they'll come back to the pack a bit, as we saw last summer when we beat India pretty comprehensively here."
As for New Zealand, Mills is confident, although he believes the days of home advantage, at least on the field, are not as pronounced as they once were. The amount of international cricket played, and the information players absorb from their travels, negates much of that. Most teams will have a good idea what to expect.
But it is off the field that Mills sees benefits for New Zealand. The comforts of home, knowing what training facilities are like, where to eat, all the small elements which go into the whole package, should be a significant help.
Mills insists the sense of anticipation is already significant and will only grow. "There's a huge buzz about the World Cup.
"Seeing the 1992 World Cup games [when New Zealand and Australia were joint hosts] on Sky has ignited a few candles for people about what it was like and I guess we're keen to replicate that, and go further," Mills said of New Zealand's march to the semifinals that year.
165 Number of Kyle Mills' ODI appearances
235 Number of ODI wickets for Mills
2 Mills' place among New Zealand's leading ODI bowlers, behind only Dan Vettori's 276 from 271 matches
