There are many measures of sustained success, but one of the most intimidating was apparent at White Hart Lane on Saturday.
They are the three survivors among the youth products christened Fergie's Fledglings, a trio of the most decorated players in the modern game and among the select band of one-club men. However, and perhaps for the first time in 17 years, it is possible that none is in Ferguson's first-choice side. Neville and Giggs, though captain and vice-captain respectively, can safely be described as squad players now. Scholes' status is the subject of greater debate: he was a regular starter before sustaining a knee injury in September.
Neville's position is under greatest threat. After a year on the sidelines, the pace of competitive football appears to have come as an unwelcome shock to him. A substandard display against Arsenal six weeks ago prompted a rethink from Ferguson, who swiftly turned to the next generation. Rafael da Silva appears the preferred right-back now and, given Wes Brown's unassuming excellence while deputising for Neville last season, the 33-year-old appears to be consigned to the fringes. If the da Silva twins are the 21st century Nevilles, Rafael's greater attacking verve ages the original model still further.
The footballing generation game can have a cruel ending: there are parallels with Paul Parker's swift descent from automatic pick to third choice. Moreover, with Neville in the final year of his current contract, neither an unconvincing outing in the centre of defence against Blackburn in the Carling Cup nor John O'Shea's ability to slot in at right-back bode well. For a man who has tried to personify the United support - not least in his attitude towards Liverpool - being discarded would be an undistinguished finish to a career at Old Trafford.
For Scholes, contracted until 2010, that day surely lies further in the future. He remains the finest passer at Old Trafford, capable of unlocking a defence with a deft touch or beating the goalkeeper with a ferocious shot, as Barcelona discovered in April.
Yet his presence on the pitch for a mere 66 minutes at Chelsea and just 55 at Liverpool is evidence of his physical failings. An ageing technician can be bypassed by athletes, and Scholes may no longer be a 90-minute player, especially when United do not dominate possession. When tiring, a poor tackler can become an unnecessary risk. And United can have a more resilient look when Michael Carrick is complemented by a workhorse such as Darren Fletcher or Anderson, though have a more inventive appearance when Scholes takes the field.
While David Beckham amassed millions of pounds, dollars, euros and headlines, the title of the greatest footballer from United's youth system in Ferguson's reign surely belongs to either Scholes or Giggs. The manager's vote would probably go to the younger man; he represents the connoisseur's choice. This pick, however, would be Giggs.
That is influenced by longevity. The Welshman was an established player before the rest of his generation emerged. Giggs' greatness is not universally accepted - indeed, he is curiously undervalued by many in Manchester - but he has defied many a prediction of his decline. In Moscow in May, Ferguson spoke of phasing Giggs and Scholes out, suggesting they may figure 25 or 30 times a season. The former already has 18 appearances this campaign, the consequence of his natural fitness and gift for reinvention.
Sadly for the nostalgic, they are rarely seen in harness. There came a time last season when it became rare for them to start together; the theory, presumably, being that younger legs could compensate for the presence of one footballing pensioner, but not two.
Now the challenge for each is to influence the game as a replacement, something Giggs managed as United clinched the Premier League title and then the Champions League in successive May matches. Ferguson has said Giggs can play on until he is 38, something Scholes, who has suffered more from injuries in recent years, is unlikely to do. And if that is the case, the first among them shall surely be the last, extending his record of United appearances towards 900 when all his contemporaries have left Old Trafford.
Not that he has a monopoly in durability: it is not beyond the realms of possibility that Ferguson will outlast them all.