At 36, wicketkeeper-batsman Haddin and opener Chris Rogers are the elder statesmen of a team of significant collective vintage.
Haddin concedes it is reasonable to point out that, after winning the Ashes before Christmas with an unassailable 3-0 lead, it will be a challenge to remain on an upward curve.
Yet that is the aim Michael Clarke's team has set itself, to try - as England managed in 2011 - to top the world Test rankings.
Haddin himself has made a habit of defying expectations not only to prolong his career but scale new heights, and is very much in the school of thought that age is merely a number.
Nonetheless, asked whether he and his team-mates may have reached their optimum together, he said: "Maybe.
"But that's something that we've challenged ourselves, to continue on the road and... to become better cricketers."
Haddin is not the only member of the team defying the calendar, with linchpin seamer Ryan Harris - previously injury-prone - bowling better than ever at 34.
"There's a lot can be made of age," Haddin added. "If we talk too much about age, I wouldn't be standing here.
"I've been told on a number of occasions I'm too old. It's not something we think too much about.
"If you're performing and keep challenging yourself to be the best cricketer you can and contribute to this group moving forward, we're comfortable with that.
"Age is not something the players are worried about."
As he approaches the Boxing Day Test at the MCG, the traditional centre-piece of the Australian season, he has his eyes on several more years at the top yet.
"I hope so," he said.
"I've said for a while that as soon as I stop challenging myself out on the training paddock to become a better player is when I give the game away - but I still see a lot of cricket in front of me.
"I feel as comfortable as I have in this environment.
"I'm really enjoying where this team is trying to go, and the brand of cricket we're starting to play.
"I'm enjoying being challenged by the group to keep getting better and keep moving forward as a group."
Even with the Ashes in the bag, Haddin is in no mood to let up against opponents who arrived here hoping to win the urn for a fourth successive time.
"I've been on the end of a few hidings from England, so from my point of view it's not that hard at all (to find motivation).
"You never take a Test match for granted. I've never played in a dead rubber - and that's from the bottom of my heart."
Rogers' opening partner David Warner, scorer of two centuries to Haddin's one in the series, is out to make sure Australia's batsmen receive the same praise as the bowlers for their impressive contribution this winter.
Bowling coach Craig McDermott has lauded his attack as the best in the world, and Warner does not think Australia's top six are too far off the same status either.
"We are well on our way," the combative left-hander said.
"We've been gelling well together... we're playing good cricket at the moment."
Warner is not minded to offer an Australian perspective on the shock retirement of Graeme Swann, or the off-spinner's controversial remarks about the arrogance he sees in some Test cricketers.
"What's happened with Swanny and the English team is their business, and we don't care what happens," he said.
"We need to really drive it into England. We are here to play our brand of cricket, and that's why we're up 3-0 at the moment."