Every squad, every All Blacks team, is feverishly debated. Every New Zealand rugby fan is an expert. But for Steve Hansen and his confidants, Ian Foster and Grant Fox, what exactly determines the art of selection?
Hansen's late father, Des, an astute coach himself, once told his son: "There's a lot of good coaches and good selectors out there, Steve, but there's not many who are great selectors and great coaches."
Hansen adds: "He said, 'I can tell you this: if you get the selection right, that will help you be a good coach'.
"To me, selection is one of the most important parts of the game."
It's also one of the most complex.
The canvas of any rugby team is painted many colours. Week to week, squad to squad, each selection stroke weighs form, injuries, workloads, combinations in every position.
As Hansen plots the All Blacks' quest for three successive Rugby World Cup titles in Japan, here he unveils his selection philosophy.
Even in the digital age, Hansen does not let numbers such as running metres or tackle breaks sway his opinion.
"Stats can be manipulated to do whatever you want with them," he says. "Yes, they're important. Are they the key thing? No. It's what you see on the park.
"You see an athlete who has energy, skill, mental fortitude. Then you look at his character. Is he the right fit for the team you want? From there it becomes either really quite clear-cut or there might be a number of people vying for that position."
One of the most difficult realms of selection, Hansen has found, is picking ripe, emerging talent at the right time.
There is no exact science. No manual to consult. Judgments are instead based on a number of factors.
"You're looking at if they can they cope with the pressure, and if they can't then they're not going to cope at this level. That tells you they're not quite ready if they're a young player. Sometimes you see a young player and you say 'he's got it' and if we support him he'll be able to do it at the next level.
"That's where you've got to go with your gut instinct but that comes from your experience and knowledge of what you've seen before so it's not as easy as it sounds.
"It's a feeling you've built up as a coach and selector throughout your tenure of doing it."
Hansen, together with Foster and Fox, nailed this aspect when they surprised many by thrusting Rieko Ioane, 20 years old at the time, ahead of Julian Savea to start his third test against the British and Irish Lions in 2017.
Earlier this year that selection trio rolled the dice again, deciding they needed to find out whether in-form Crusaders wingers George Bridge and Sevu Reece were ready for the World Cup by throwing them in the fire for the deciding Bledisloe Cup test at Eden Park.
On both those occasions, calculated gambles paid off. But Hansen admits he doesn't always get it right.
"If the risk is too high for the reward then don't do it but if the risk is minimal and the reward is really high then full your boots."
The case Hansen regrets came alongside Graham Henry, Wayne Smith, and the late Brian Lochore when they rushed a 19-year-old into the All Blacks.
"Everyone makes mistakes. You don't make them by yourself. There's a group who picks the team so you can't take all the credit and you can't take all the blame either.
"I look back on my time as a selector and I have definitely picked a couple of players that weren't ready. It's not you pick the wrong person, sometimes you pick them too early.
"I look at Isaia Toeava as one of those. He was probably the most talented rugby player I've ever seen and we put him in the team too early.
"It's an easy mistake to make. You think he's got all the rugby attributes but that's where you learn they've got to have the mental fortitude to cope with that whole thing.
"You feel bad about that because there's a young man who went on and won a World Cup medal but we didn't see the best of him because we put him under too much pressure too early."
Setting guiding principles and being clear about what the team is trying to achieve, the style of rugby they want to embrace against specific opposition, helps form selection logic, even when the three-man panel don't always agree.
Hansen brushes off the suggestion he is loyal to senior All Blacks but acknowledges some in that bracket receive more wriggle room than others when tournament squads are selected.
"I don't think that comes into it. The biggest loyalty you've got is to the team. If you're loyal to that philosophy then when you have to make hard decisions about an old guy or younger guy you make it for the right reasons.
"A number of times we've seen current All Blacks who aren't playing that great at Super Rugby but they've got All Black form in the test arena so you know they can do the job mentally, physically and from a skill point of view.
"The art then is working out why they aren't playing that well in Super Rugby and there could be a number of reasons. Once you get that information you say can I fix that or can't I? And if you can, then you go for it because you know they can play there.
"Whereas a young guy who hasn't played for the All Blacks you can only judge him on what you know."
Flick on the radio, pick up the paper, chat with friends and family, wander down the local pub and Hansen does not lack for selection advice.
New Zealand's extremely passionate rugby public is not shy in expressing their views, many of which are often skewed by local allegiances.
Blocking out these external influences can't always be easy but Hansen notes public opinion is all care and no responsibility, while for the selectors it's all care all responsibility.
"You've got a responsibility to make sure you push that aside. Your job as a selector is to pick the best team that I believe is right for whatever game or tournament we're going to. As a three-man panel it's our opinion that gets tested.
"I've been fascinated over the years. I read and hear stuff from people who don't understand the major differences between tighthead and loosehead prop. Selection is not easy. It's actually quite a complicated art and you've got to get it right."
Hansen is attending his fifth World Cup. Since 2012, he has led the All Blacks in 104 tests. In that time he's cut countless world-class fringe players and leading figures. Centurion prop Owen Franks was the latest example – Julian Savea another.
"It's not easy for a number of reasons, particularly when you've got a lot of talent because you have to sort it out.
"It's not easy because you've got to tell some people that they're not in. That's probably the hardest thing you have to do as a selector. Sometimes that's with people you've travelled a lot of miles with.
"But if you build selection around what's right for the team, then you don't have a choice. It's never easy but when you have that hard conversation then you try to do it as caring, honest and empathically as you can."
Much of these instincts come from Hansen's gut. A sense, a feeling, based on what he sees, hears and what his experience tells him.
His record as All Black head coach – 91 wins, nine losses, four draws – suggests he has mastered the art of selection.
OPINION: There are three key reasons to believe that they can.