Is three years long enough for a foreign player to become what they call naturalised? Who knows?
If you asked Ireland's new recruit Jared Payne back in the autumn of 2011 when he ruptured his Achilles tendon for Ulster, he probably would have said it was too long.
How does he feel about those who say it isn't long enough? "People are entitled to their opinion. They can say what they want," he said casually.
"If you get annoyed by it, you're only going to beat yourself up over it.
"Coming over here, you grow the passion to play for Ireland for the last few years.
"I'm pretty passionate about it, seeing the environment Ireland have created over the last three years. It is something I want to be a part of."
When the avenues to international rugby were closed off by the form of Conrad Smith and Israel Dagg, and others, in New Zealand, Payne was open to what Ulster's David Humphreys had in mind.
"Look, I had to make a pretty tough decision when Ulster came and asked me to come over. I had to make my bed and I always wanted to do a bit of travelling.
"David talked from the Ulster side of things and I thought, 'why not give it a crack?'
"I was signed as a project player. The possibility (to play for Ireland) had been mentioned further down the track. It was part of the deal. But, I was more short-term focussed.
"It wasn't something I hung onto."
Now, Payne will sample international rugby with many of the men he has seen as rivals over the last three years.
"I think the player I've only really played with is Tommy (Bowe), so it's going to be all a new experience," he enthused.
"But I can't wait. Johnny's (Sexton) one of the best fly-halves around. He gives you time on the ball and, with Robbie at twelve, hopefully, we can carry the ball and get over the gain line.
"And then you've got someone pretty exciting like (Simon) Zebo and Rob (Kearney) at the back, so it's going to be good. I just can't wait to see how it all comes together on the field."
It came together well enough on the training pitch for Schmidt to side with Henshaw and Payne over the merits of a fit-again Gordon D'Arcy, Ian Madigan and even Stuart Olding.
"What I saw of both of them is an ability to carry ball, an ability to distribute ball, an ability to work hard defensively and be physical defensively," said Schmidt.
Simple as that. No instant chemistry.
"To make a pairing of them, I don't think that's going to happen overnight," cautioned Schmidt.
"I think inevitably there are going to be things that we progress from this Saturday through the succeeding weekends, and there will be changes through the succeeding weekends.
"So this combination obviously won't last throughout the series but I'm reasonably excited about seeing how they do adapt and equip themselves in an incredibly challenging environment."
The Irish coach is not expecting perfection. He just needs to see enough to believe the partnership can work in the long-term.
"I'm looking forward to seeing how they measure up. I guess it's incredibly difficult (to know)," he said.
"There's no soothsayer. There's no-one who can predict how it will go.
"But, we can influence how it will go by the preparation we've done and that continuity through three or four trainings.
"They matched up as a pairing, hopefully that's sufficient to give them the confidence to link well and perform well on Saturday."
South Africa coach Heyneke Meyer has embraced the confidence of youth by grooming out-half Handre Pollard (20) and centre Jan Serfontein (21) for the 2015 World Cup.
"Handre and myself have got to know each other quite well. Our defence is quite solid," said Serfontein.
"But, you must expect anything at any time in a game so we will always be ready.
"We try to play the situation," he said.
South Africa will have little footage on Henshaw at twelve where he will have to be a quick learner.
They will have none of Henshaw and Payne together and that is what makes the combination so exciting and, yet, so worrying.