During the best part of a century of squabbling for supremacy in their corner of the capital, Arsenal and Tottenham seemed polar opposites. When the Gunners prioritised pragmatism over purism, Spurs were invariably entertainers. When Arsene Wenger rebranded Arsenal as money-conscious champions, Tottenham were expensive underachievers. Whatever one half of the North London felt about Sol Campbell, the other thought the exact opposite.
But now, separated by one point and one place, and with a shared aim of qualifying for next season's Champions League, they have much in common. And, regardless of which European competition they enter, that should extend to their summer dealings. Ambitions should show similarities: whether ensuring the experienced manager stays or keeping the star players; whether extending Robin van Persie's time at the Emirates Stadium or repelling interest in Gareth Bale and Luka Modric.
If both may fear raids by the super-rich for their star men, their transfer policies should be the same. For incomings, the policy ought to be one of quality not quantity. For outgoings, the opposite approach is required. Because, while both have appeared depleted at times over recent weeks, they actually have a surfeit of players.
Plenty of clubs have stockpiled footballers, but few more obviously than the North London rivals. Between them, they have 36 out on loan. Some, of course, are youngsters getting a grounding in first-team football, but others are more senior figures whose services have not been required this season. They may not be needed again.
Out of sight and out of mind they may be, but the objective ought to be for Arsenal to cash in on Andrei Arshavin, Nicklas Bendtner, Denilson and Carlos Vela; for Spurs to sell Jermaine Jenas, David Bentley, Sebastien Bassong and Bongani Khumalo.
While bargain-hunting and talent-spotting are skills both clubs have demonstrated over the years, another, less heralded, knack is needed: to find new employers for the unwanted. That, in turn, reduces the wage bill and frees up funds, not to mention places in the 25-man squad.
At Arsenal, at least eight (and potentially as many as 10) should be surplus to requirements. Once an expert in selling footballers before their market value declined, Wenger has been slow to part company with underperforming players. Yet besides the quartet above that he has farmed out, it is evident that four more - Manuel Almunia, Sebastien Squillaci and the perennial bench-warmers Park Chu-Young and Marouane Chamakh - do not enjoy his confidence either. In addition, Johan Djourou has regressed and Abou Diaby is an increasing source of frustration, partly because of his inability to stay fit. The majority of supporters would happily bid both farewell.
If none will generate huge fees, they do not necessarily need to. After previous sales and after a profitable summer of 2011, Arsenal should have around £50 million to spend. Departures could swell that past £70 million. The task is to find footballers who can be peers for Van Persie - perhaps a pair of attackers and defenders - and the proposed signing of Lukas Podolski, given his record for Germany, seems auspicious. The time for bringing in peripheral players has past; proven performers must be targeted.
Tottenham have also been in the black in the last two transfer windows and, if their interest in Eden Hazard is to be realised, may have a similar budget. When Emmanuel Adebayor's loan from Manchester City ends, recruiting either the Togolese or a striker of a similar ilk on a permanent deal should top the priority list. But, as at Arsenal, the exit door should be more populated than the entrance.
Jake Livermore's emergence ought to render Jenas unnecessary. They will have to write off much of their expenditure on Bentley and Giovani dos Santos, two 2008 signings, while Heurelho Gomes should not spend a second season as a third-choice keeper. Bassong's sale has long been likely - indeed, it almost happened in August - while in other positions Spurs have an enviable array of riches. Steven Pienaar, who has been borrowed by Everton, and Niko Kranjcar are skilled technicians in midfield, but, given their similar styles, it is hard enough to get one regular football, let alone both. Vedran Corluka and Kyle Naughton, both loaned out now, cannot both understudy Kyle Walker at right-back.
Sales should be eased by the knowledge that both clubs are producing the next generation of players. Besides Livermore, Danny Rose, Steven Caulker, Andros Townsend and Tom Carroll could figure more prominently next season. Rather than Denilson and Diaby, Arsenal's back-up central midfielders should include Francis Coquelin, Emmanuel Frimpong and Henri Lansbury, who have all shown potential this season. Ryo Miyaichi, impressing at Bolton, could be an attacking alternative on the bench. Rather than the jaded faces of old, these are more progressive picks to fill up the squad and, wage-wise, cheaper than the current choices.
So Arsenal and Tottenham should enter the summer with the same three-point plan: to keep, then recruit, high-class individuals and bid farewell to the seasoned figures from the fringes of the squad. Such clearouts may not seem lucrative but, as salaries are often the biggest cost in football now, could save a fortune. The ultimate task for both will be to remove men who are supposedly assets on the balance sheet but, for various reasons, rarely on the pitch, and allow the money to be reinvested in strengthening the side.