Bowlers James Anderson and Stuart Broad should not play together for England in the future as the side build towards regaining the Ashes in Australia, says former captain Michael Vaughan.
Anderson, 38, and Broad, 33, are England's leading Test wicket-takers with 575 and 467 respectively.
But Vaughan says England have to be "realistic" about the pair's prospects of reaching the next Ashes in 2021-22.
"I don't think it is right both of them play now," Vaughan said.
"It might be that Broad plays one series and Anderson plays one series.
"They are not going to like it, but they are at that stage of their careers where England are going to have to manage the combination very smartly."
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Anderson bowled just four overs in the 2019 Ashes series - which ended in a 2-2 draw when England won the fifth Test on Sunday - after he injured his calf in the first Test.
Broad was England's most successful bowler in the series with 23 wickets at an average of 26.65, but will be 35 when the next Ashes series begins down under.
|England's leading Test wicket-takers|
England's next Test series, which will be their first under a new coach following the departure of Trevor Bayliss, is away against New Zealand in November and Vaughan believes they must introduce a similar vision to the one which led to the 50-over team winning the World Cup this summer.
He said selectors may have to make a "big call" and leave one of their three wicketkeeper-batsmen - Jonny Bairstow, Jos Buttler and Ben Foakes - out of the squad, and should also introduce younger batsmen such as Dominic Sibley, Zak Crawley or Ollie Pope to their top six.
"I want to see a disciplined way of playing and the World Cup is in the bag now," Vaughan said on BBC Radio 5 Live's Tuffers & Vaughan show.
"The most important thing going forward is the Ashes in two years.
"It is the Test team that needs a real focus over two and a half years of real dedication and structure.
"It might be that some of the players who play all of the formats miss white-ball series to make sure that when the Tests are on they are absolutely fresh and ready to bat seven hours, because to win in Australia that is exactly what you require.
"You need a relentless nature with the ball and relentless discipline with the bat - and it has to come over a two-and-a-half-year window."