Cape Town - “Been there, done that” ... it is usually said with good reason.
The phenomenon is very much applicable, too, when it comes to the huge imbalance in World Cup knockout-phase experience between the Springboks and their quarter-final foes in Tokyo on Sunday, host nation Japan.
Between 11 of the 23 Bok match-day squad members for the clash, there are 32 past instances of involvement in the advanced stages (last-eight onward, including bronze playoff matches) of the tournament.
Japan? None: this is their first savouring of the unique demands of RWC knockout play.
The Boks who have played in this pressure-cooker environment before, from Sunday’s starting line-up, are Willie le Roux, Damian de Allende, Handre Pollard, Duane Vermeulen, Pieter-Steph du Toit, Lood de Jager, Eben Etzebeth, Frans Malherbe and Tendai Mtawarira.
Substitutes Francois Louw and Frans Steyn, meanwhile, have also played rugby at that advanced level.
The most experienced KO-phase customer on show will be versatile loose forward Louw, who has taken part in four: it all began for him with his presence in the Bok side which so controversially (thanks largely to the refereeing of Bryce Lawrence) lost the 2011 quarter-final to Australia 11-9 in Wellington.
He then represented the green-and-gold cause in three knockout matches at the 2015 tournament in the UK: the victorious quarter-final against Wales and third-place playoff against Argentina, and the semi-final defeat to the All Blacks.
Those three matches in 2015 are exactly the same ones relevant to Le Roux, De Allende, Pollard, Vermeulen, De Jager, Etzebeth, Malherbe and Mtawarira.
Du Toit got a cap as a reserve in that Wales quarter-final at Twickenham, while the only exception to the rule - courtesy of much earlier exposure to World Cup knockouts - is Steyn.
Then a notably raw but amazingly “BMT”-laden utility backline factor, the now 32-year-old played in all three pivotal matches for the Boks in their triumphant 2007 World Cup, the victories over Fiji (quarter-final), Argentina (semi) and England (final).
He was injured ahead of the knockout phase in 2011, and not available for the 2015 tournament.
Another seasoned player, Mtawarira, had some involvement in the 2011 tournament, though not as a match-day presence into the Boks’ short-lived knockout campaign.
Those 11 current Boks who have been in the 32 collective knockout matches before, have enjoyed victory on 22 occasions, while suffering 10 defeats - a win percentage of 68.75.
It is just one extra reason why South Africa are considered quite strong favourites by the bookies against the KO-phase first-timers on Sunday ...
15 Willie le Roux, 14 Cheslin Kolbe, 13 Lukhanyo Am, 12 Damian de Allende, 11 Makazole Mapimpi, 10 Handre Pollard, 9 Faf de Klerk, 8 Duane Vermeulen, 7 Pieter-Steph du Toit, 6 Siya Kolisi (captain), 5 Lood de Jager, 4 Eben Etzebeth, 3 Frans Malherbe, 2 Bongi Mbonambi, 1 Tendai Mtawarira
Substitutes: 16 Malcolm Marx, 17 Steven Kitshoff, 18 Vincent Koch, 19 RG Snyman, 20 Franco Mostert, 21 Francois Louw, 22 Herschel Jantjies, 23 Frans Steyn