Toulon owner Mourad Boudjellal may have just discovered this after witnessing the disappointing form of star signing Julian Savea, but it's something New Zealand rugby fans, coaches - and players - have known for decades.
The likes of John Kirwan, Bryan Williams, Jeff Wilson and now Ben Smith are the pasta in the cupboard, in contrast to the cream in the fridge that represents the majority of wingers who have represented New Zealand.
Most of New Zealand's outside back representatives have fleeting international careers – a season or two, a handful of games – when they're at the peak of their powers.
Even our greatest fliers have a relatively brief period of time to make their mark before their gifts fade.
As Richard Knowler points out, Savea's prolificacy was waning before his test career ended.
He's not the only All Blacks wing to discover that five years at the highest level as a first-choice selection is close to the limit of excellence, while few are still at their peak aged 26.
All Blacks rugby is littered with wingers who were stars at their best but played for less than half-a-decade with the national side. Among them - Grant Batty, Inga Tuigamala, Zac Guildford, Craig Green, Richard Kahui, Ron Jarden and Grahame Thorne.
Many of them make their debut as youngsters and find their All Blacks career is over in their mid-20s - some by choice, others by the will of selectors.
The reasons for this short tenure can be multiple – chiefly injury, which hampers the player's turn of speed; usually the winger's greatest weapon.
Yet even the international careers of the likes of Batty, Thorne and Kahui are lengthy in comparison compared to most, especially those who start young.
Jasin Goldsmith and Craig Wickes were teenage debutants who never played a test and had their careers derailed by injury. Others who flirted with the briefest of All Blacks careers on the wing included Terry Morrison, Terry Mitchell, Scott Cartwright, Robert Kururangi, Ken Taylor, Bruce Reihana, Sosene Anesi, Anthony Tuitavake and Lelia Masaga.
But even our most prolific tryscorers – and long-term representatives – suffered a notable drop in productivity towards the end of their All Blacks careers.
Fullback - and sometimes centre – Christian Cullen was an instant sensation, debuting for the All Blacks aged 20, but he played his last test as a 26-year-old. He only played seven tests in his final two years in the black jersey, scoring four tries, three coming in one game against Fiji as injuries took their toll.
Doug Howlett, our most prolific test try-scorer with 49 in 62 appearances, had eight years as an All Black after debuting as a 21-year-old, but played only eight tests in his last three seasons while Joe Rokocoko – 48 tries in 68 games – made his bow at 20, played his last aged 27 and scored only four tries in his last three seasons before heading to France.
Sitiveni Sivivatu made his All Blacks in debut aged 23 in 2005 when the Fijian-born winger became eligible and his last test came six years later. He played 10 times for the All Blacks in 2009 but scored just three tries, didn't feature in 2010 and ended his test career with two appearances in 2011.
Smith may be the greatest outlier of them all – he played his first game for the national side in 2009 at the “late” age of 23 and while he's divided his international time between wing and fullback (with the odd sortie as centre), his 76 tests over a 10-year span while still being a first-choice at 32 bucks the trend like none before him.
The current All Blacks wing sensation, Rieko Ioane, played his first test before he turned 20. He's now scored 22 tries in 24 tests – a rate which sees him on track to overtake Howlett as our most prolific.
But how long will he be an All Black for?
- Ian Anderson/Stuff
At A Glance
Career longevity of standout All Blacks wings: Grant Batty – debut aged 21; last test aged 25, Christian Cullen – debut aged 20, last test aged 26, Bernie Fraser – debut aged 26, last test aged 31, Craig Green – debut aged 22, last test aged 26, Zac Guildford – debut aged 20, last test aged 23, Doug Howlett – debut aged 21, last test aged 29, Rieko Ioane – debut aged 19, now aged 21,
Ron Jarden – debut aged 21, last test aged 26, Richard Kahui – debut aged 23, last test aged 26, John Kirwan – debut aged 19, last test aged 29, Jonah Lomu – debut aged 19, last test aged 27, Joe Rokocoko – debut aged 20, last test aged 27, Julian Savea – debut aged 21, last test aged 26, Sitiveni Sivivatu – debut aged 23, last test aged 29, Ben Smith – debut aged 23, now aged 32, Grahame Thorne – debut aged 21, last test aged 24, Inga Tuigamala – debut aged 20, last test aged 24, Bryan Williams – debut aged 19, last test aged 28, Jeff Wilson – debut aged 19, last test aged 27, Stu Wilson – debut aged 22, last test aged 29.