"Today we are playing 14 or 15 test matches alone and you just can't ask the same people to do it all the time and expect them to play to the level we expect them to."
Using an expanded squad and splitting them into two groups is not necessarily a new concept for the All Blacks.
Last year a handful of senior players didn't travel to Argentina and instead went to South Africa.
Later in the year extra players were drafted in to play a game against a French XV, which allowed the majority of the team that was playing Scotland five days later to prepare for that test at the same time.
The scenario of sending 23 players to London three days before the other group plays Japan is really just an extension of the same theme.
The point of them going earlier is so they can get a head start on their recovery and be able to better prepare for back-to-back test matches that will be physically demanding.
"Over the last few years we have looked at different ways to skin the cat," says Hansen.
"Last year we split the squad to Argentina and South Africa this year the opportunity to play the Bledisloe Cup up here [Japan] was too good to turn down because of the opportunity to experiment and get a feel for Japan and the idea of having two weeks here was better than having one.
"Once we decided that we had to ask how that was going to affect us against England, Ireland and Italy and we chose to take some extra players.
"It cost us nothing because the game is an extra and we are winning everywhere when you think about it…we are getting to give some guys some really valuable experiences, we will get to see whether they can cope.
"This is a young side, there is no disputing that but as I said, the expectation is that they go out and play really well. That puts a bit of pressure on them but you get to see how they perform under that pressure which then gives you an opportunity to make some sound judgements when you need to about the selections that are coming up next year."
In particular, there will be significant focus on the back three, Vaea Fifita and both Patrick Tuipulotu and Jackson Hemopo at lock.
At the moment the All Blacks have Ben Smith, Rieko Ioane, Jordie Barrett and Waisake Naholo penciled in as their outside backs to take to the World Cup.
But they have room to play around with that given the versatility of Smith and the ability of Damian McKenzie to play fullback.
Milner-Skudder's different skills portfolio remains of interest but the selectors need to see more evidence that his sharpness has fully returned.
Fifita is in a scrap with Shannon Frizell and Jordan Taufua to fill one of the likely loose forward spots and Tuipulotu and Hemopo are both playing to persuade the selectors they should take four locks to the World Cup rather than the three they took in 2015.
"It's a test match that brings no more apprehension than any other test match," says Hansen.
"People are trusted to enhance the legacy and the expectation is that they go out and play well. For them to do that then we have to go out and coach well. It is the same every time we play."
