As Alastair Cook approaches his 150th Test appearance this week at the WACA Ground, it was inevitable that most questions were centred on how long he has left playing at the top level.
Several high-profile names have suggested the opener already looks like he is done, his former teammate Kevin Pietersen last weekend suggesting Cook had lost the "fire in his belly" to carry on.
Those comments were echoed by Mitchell Johnson in his column for the UK's Daily Telegraph, the former Australia fast bowler saying: "I think he is on his last tour.
"I ran into Cook at Richardson Park during England’s practice game over the weekend and asked him how he was feeling. He didn’t give away too much, just shrugged his shoulders.
"Like in 2013-14 he seemed a bit down, but this time he definitely does not have that look of determination in his eye, that desire.
"He didn’t score runs in England’s three practice games and he is averaging 15 in this series: I don’t see that fire in his belly any more."
Former Australia captain Ricky Ponting had stated before this Magellan Ashes Series began that he thought Cook would quit Test cricket sooner rather than later after giving up the England captaincy at the start of this year.
But whatever the truth – and only Cook knows if he will play on beyond this tour – the fact he is still opening the batting for his country more than 11 years after his debut against India at Nagpur is remarkable.
Only Australian great Allan Border, with 153, has played more than Cook’s 147 consecutive Tests. Indeed, the only match he has missed was the third and final Test of his debut tour in India back in 2006, when he was laid low with a stomach bug in Mumbai.
It's a fine achievement but the fact he holds the record for most England Test appearances – Alec Stewart with 133 is his closest rival – does suggest the time to retire is close.
What else does Cook, who turns 33 on Christmas Day, have left to prove?
He has already won four Ashes series, has won series' in Australia, South Africa and India, and has the most Test runs (11,961) and centuries (31) of any Englishman.
Speaking in Perth on Tuesday, Cook said: "I probably didn’t think I would be here when I turned up in Nagpur all those years ago.
"It’s obviously a very special moment in terms of a personal milestone. Not many people play 150 Test matches so to do that and do it at the top of the order, I’m quite proud of that. Hopefully there can be a few more after."
However, Cook, who made his 100th Test appearance at the WACA on England’s last Ashes tour in 2013-14, was unconvincing when pressed on how long he wants to carry on playing for his country.
"Ultimately, I don’t know, I haven't made any decision on anything," he said. "All my focus is on this game, we have the biggest game of our lives coming up."
Indeed, there was even a Freudian slip during one response. "It’s a very proud moment when you play for England, whether it’s at the very start of your career or your last – I mean 150th – game," he said. "I didn’t mean that. That was a very bad slip of the tongue. I meant to say latter part of your career."
But what about those comments from Pietersen and Johnson?
"They are very easy comments to make when judged on two games," he replied. "I hadn’t seen Mitchell Johnson since 2014 before I bumped into him walking to this interview. For him to judge is just filling column inches. The amount of work I've done in the last few days, extra stuff, shows I'm still hungry."
But could this be his last series?
"To be honest with you, I have no idea," said Cook. "And I’ve said that since I gave up the captaincy. The results justify the means. If you’re scoring runs all the time, your place is guaranteed. And if you don't, there are plenty of other people who want your place so that hasn’t changed.
"People want your place and it’s up to me to score runs to get those people off my back."
And there’s the rub. Cook is not old, even in sporting terms. He could have another three or four years at the top as long as he still wants it and does score those runs.
One can’t come without the other and it is his end product – those runs – that have tailed off dramatically over the past year or so.
At the start of 2017, Cook’s Test average was 46.45. But after a year so far that has seen him score just one hundred and average 37.29, that has now dropped to 45.84.
In fact, Cook has averaged in the 30s in Tests for three of the past five calendar years, interspersing those with decent 12-month periods in 2015 (average 54.56) and 2016 (42.33).
The raw stats, though, suggest Cook hit his peak in 2011 and in 2012.
In 2011, he was named the ICC’s Test player of the year after hitting 927 runs at 84.27. This was the year England reached No.1 in the world Test rankings and it, of course, started with a century in Sydney during an Ashes series which England won thanks in large part to Cook’s 766 runs.
In 2012, Cook’s average 'dropped' to 48.03, but it was a year that produced his finest hour – three centuries during a series win in India in what was his first assignment as Test captain.
Now, five years past what were unarguably his peak years, Cook may decide this is the right time to go.
Hopefully he has something special left to produce in this Ashes series before he does go.
At 2-0 down, England really could do with it.
2017-18 International Fixtures
Magellan Ashes Series
Australia Test squad: Steve Smith (c), David Warner (vc), Cameron Bancroft, Usman Khawaja, Peter Handscomb, Shaun Marsh, Mitchell Marsh, Tim Paine (wk), Mitchell Starc, Pat Cummins, Nathan Lyon, Josh Hazlewood, Jackson Bird.
England Test squad: Joe Root (c), James Anderson (vc), Moeen Ali, Jonny Bairstow, Jake Ball, Gary Ballance, Stuart Broad, Alastair Cook, Mason Crane, Tom Curran, Ben Foakes, Dawid Malan, Craig Overton, Ben Stokes, Mark Stoneman, James Vince, Chris Woakes.
First Test Australia won by 10 wickets. Scorecard
Second Test Australia won by 120 runs (Day-Night). Scorecard
Third Test WACA Ground, December 14-18. Tickets
Fourth Test MCG, December 26-30. Tickets
Fifth Test SCG, January 4-8 (Pink Test). Tickets
Gillette ODI Series v England
First ODI MCG, January 14. Tickets
Second ODI Gabba, January 19. Tickets
Third ODI SCG, January 21. Tickets
Fourth ODI Adelaide Oval, January 26. Tickets
Fifth ODI Perth Stadium, January 28. Tickets
Prime Minister's XI
PM's XI v England Manuka Oval, February 2. Tickets
Gillette T20 trans-Tasman Tri-Series
First T20I Australia v NZ, SCG, February 3. Tickets
Second T20I – Australia v England, Blundstone Arena, February 7. Tickets
Third T20I – Australia v England, MCG, February 10. Tickets
Fourth T20I – NZ v England, Wellington, February 14
Fifth T20I – NZ v Australia, Eden Park, February 16
Sixth T20I – NZ v England, Seddon Park, February 18
Final – TBC, Eden Park, February 21