TOUGH JOB AHEAD: Steve Hansen will ring in the changes slowly with the All Blacks.

As the All Blacks leadership sat in a room together in Auckland recently the issue became crystal clear.

No need to produce birth certificates. Most of those present were on the wrong side of 30 as they sat down with coach Steve Hansen to plot the first real step toward their 2015 Rugby World Cup defence.

It was a watershed moment according to centre Conrad Smith who says the meeting forced the group to collectively confront the fact that for some the next showpiece tournament might be a step too far.

"It was the first time we all brought up that most of us sitting in the room were on the other side of 30," the Hurricanes captain said.

"We've been through all of this before during the buildup to the last World Cup and, if we're being honest, there was a concern that if some of us don't get to the next one it will leave a bit of a void."

And so some urgency is being injected into the creation of the leadership group Hansen hopes will form the core of a cup-winning squad.

Among the current All Blacks set-up there is a decent chunk of ageing men including Smith, Richie McCaw (32), Dan Carter (31), Keven Mealamu (34), Ali Williams (32), Ma'a Nonu (30), Tony Woodcock (32), Cory Jane (30), Andrew Hore (34) and Piri Weepu (29).

Will their bodies survive the next three seasons? Will the passion still burn? Will a young player simply pass them in the night?

They are the great unknowns, but Smith makes it clear there will be no sentimentality in selection.

"I want the All Blacks to win in 2015 whether I'm there or not. We all agreed that's where we needed to be at," he said.

"At the start of the meeting some of the guys were honest and said they didn't even want to think about it [2015], but I think for the sake of the All Blacks we have to approach it from that viewpoint. So that's how it progressed.

"I'm almost at the stage where, yep, I'm loving it right now, but it's a year by year thing."

Smith admits he's unsure how he'll feel in three years' time.

"I've been doing this for 10 years now, that's a large chunk of my life. If the desire is still there and I'm healthy and feel the team still needs me then absolutely I'd commit myself, but rather than make that decision now I'll make it closer to the time.

"If I'm not playing I want to be there watching them win and saying, ‘I played a small part in that. Four years ago when we started planning I was there adding my piece'. I'd take a certain amount of pride in that."

And so, the crystal-ball gazing begins.

When the All Blacks beat France in the cup final two years ago there were four 30-plusers on Eden Park in McCaw, 30 at the time, Brad Thorn (36), Mealamu (32) and Woodcock (30).

The majority of the side were in their late 20s with Israel Dagg (23), Aaron Cruden (22), Sam Whitelock (22) and Owen Franks (23) the youngest on show.

Cast back further to 2009 and it's notable how many players dropped out over the next two seasons. Eighteen would miss the cut in 2011 including such stalwarts as Rodney So'oialo, Joe Rokocoko, Sitiveni Sivivatu and Jimmy Cowan.

Interestingly, two of the Rugby Almanack's five promising players of 2009, Cruden and Whitelock were on the field in the 2011 final.

So who will make it to the start line in 2015 and who won't? Will a new star emerge? And what might the All Blacks side look like?

History shows a bunch of ageing players will not make it.

In some cases it's no cause to fret with depth already building nicely. And in these days of sabbaticals, managed workloads and endless body rubs, old carcasses can be kept running like a trusty Japanese import.

But contingencies are needed and Hansen's focus will be sharpest at hooker, midfield and wing.

McCaw is, in some ways, the least of his concerns. If he makes it as a talismanic freak of nature in the mould of Brad Thorn, then it will be a bonus.

If not, Ardie Savea and Sam Cane are poised, while blindside is a traffic jam of talent with Brad Shields, Steven Luatua, Victor Vito, Liam Messam and possibly Jerome Kaino all in the mix.

Luatua's ability to cover lock could become an asset and it will be interesting to see his progression.

The midfield is a minefield. Hansen's annoyance at Richard Kahui and Rene Ranger's pending overseas moves is understandable.

Conrad Smith and Ma'a Nonu will be 33 in 2015. That's old for the backs where speed and reaction time tends to diminish after 30.

Ben Smith is an option, Francis Saili has emerged, but it is hard to go past the return of Kahui and Sonny Bill Williams as a dream scenario.

For the injury-prone Kahui, Japan could be the perfect tonic.

Charles Piutau has the skill set for centre, but shorter term his power and pace could be utilised on the right wing.

Frank Halai is intriguing, but too early to judge, Hosea Gear is quality, but ageing, Jane's knee is an unknown and Ben Smith and Alapati Leiua look to be utilities rather than test finishers.

Carter should be packed in cotton wool. He is a once in a generation first-five eighth. A third World Cup will be a stretch at 33, but he's that good.

If not, Aaron Cruden is entering his prime, while Beauden Barrett's maturation continues.

It is of course all speculation.