Mitchell Johnson doesn’t need to look far afield to know that his days as an international cricketer are numbered.

Since he first donned an Australia uniform a decade ago, he has seen 10 fellow Test quicks (those who have played 10 Tests or more) leave the game on their own terms or at the behest of selectors at an average age of 32 years and six months.

Only Glenn McGrath, whose rhythmic action and resilient body saw him push his remarkable career within sight of his 37th birthday, and Ryan Harris who looked to soldier on past 35 until his dodgy right knee gave out, have extended their fast bowling careers beyond the age Johnson will be at summer’s end.

So it would have been disingenuous for Australia’s top-ranked quick, who now sits equal fourth on the list of his country’s all-time Test wicket-takers alongside Brett Lee, to bunt away yet another question about his cricket longevity when he fronted media at the WACA Ground this afternoon.

"I think about it most days," Johnson said bluntly and somewhat disarmingly when quizzed as to whether the thoughts of retirement he floated at the end of the failed Ashes campaign had crystallised further.

"It is probably getting to be that time, but to be honest I am just trying to play each game and enjoy it like I have said before.

"It could be after this game. I might just go ‘I am done’, but I’m still enjoying my cricket at the moment and enjoying the challenges.

"It is a really good time for Australian cricket with these young guys in the team and I want to be a part of that.

"As long as I am performing well and doing my job in the team, then mentally I am good."

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If, as chair of the national selection panel Rod Marsh indicated before the current Commonwealth Bank Test series against New Zealand began, performances on the board are a key consideration when assessing players’ merit then Johnson might be left alone to name his own departure date.

Over the past 12 months, he sits among the top 10 Test wicket-takers with 40 scalps from 11 matches, although his average of 32.45 is the most extravagant of that group and his strike rate of a breakthrough every 53 deliveries is inferior to only New Zealand’s Trent Boult (57.18).

What’s more, he and Sri Lankan seamer Dhammika Prasad are the only two among the top 10 not to have collected a five-wicket haul in Tests over the past 12 months.

Johnson could well have remedied that anomaly if only his fielders had supported him, with the handful of chances that were turfed from his bowling in the opening Test in Brisbane this week bound to stretch the patience of any sportsman, let alone one approaching ‘grumpy old’ territory.

"It's disappointing at the time," Johnson said of the muffed catches that would otherwise have seen him sitting clear of Lee on 310 Test wickets and inching ever closer to his mentor Dannis Lillee’s mark of 355.

"Especially when you've worked so hard on a plan, and you're in your 30th or 40th over and you're absolutely stuffed and a catch goes down.

"But look, we all drop them.

"I've dropped some simple ones and it's not the nicest thing when you're on the other end of it."

Dennis Lillee in 1974 // Getty Images

Unlike others such as Harris and Lee, who was unable to sustain the blistering pace of his pomp due to the attritional toll fast bowling had taken on his body, Johnson feels he is still in sufficiently good physical shape to keep pounding away.

Not that he doesn’t feel the wear and tear of a pastime that, as the recent stocks of Australia’s young fast bowlers undergoing lengthy physical rehabilitation programs bears testament, places an unnatural strain on developing and mature frames alike.

"You have your niggles here and there and just like every fast bowler that has been before me, you have your little issues that you have with your body and I am no different," Johnson said.

"That is part of being a fast bowler, you are going to be sore when you play and I like that feeling of having that soreness.

"It doesn’t sound great but I like that feeling.

"It feels like I am doing something out there and pushing my body to its limits.

"As long as I keep doing that maintenance and looking after myself after each game then I will be right to play on."

But play on for just how long is a question that Johnson cannot answer, or one that chooses not to canvass publicly just yet.

Australia’s wicketkeeper Peter Nevill said today that he could not split Johnson and his new-ball partner Mitchell Starc as to which one was hitting his gloves harder during the opening Test at the Gabba.

And the notion of wanting to end his career on the high of a home summer and a celebratory lap of a much-loved local venue before adulatory fans is not one that has crossed his mind.

Largely because thoughts of imminent retirement have yet to take root there either.

"I'm not emotional or anything like that right now, because I'm not retiring, but it's always special playing here (in Australia) so it does excite me," Johnson said about the prospect of a send-off similar to those enjoyed by McGrath, Shane Warne, Ricky Ponting, Adam Gilchrist and Steve Waugh.

“" started my career in Australia, played my first Test at the Gabba (against Sri Lanka in 2007).

"I think I'd like to finish my career in Australia if I had the choice.

"It's whether I get that choice or not - not many people get it, so who knows?

"I feel like I'm still performing pretty well. I'd like to get a few more wickets but I don't feel like I've dropped off too much; my pace is still up there and I feel confident in myself."

Johnson and Lee - fast and furious // Getty Images

Whether he can maintain the physical workload and the mental grind that comes with endless touring, relentless playing schedules and the conflicting demands of family life at home in Perth in order to challenge Lillee’s Test wicket benchmark is the other unanswered question.

At the rate he collected scalps of late, that goal could see him extend his playing days into the next Australian summer that will feature a hefty seven Tests against South Africa and Pakistan.

With overseas Test series in New Zealand and Sri Lanka before then.

But Johnson has played enough cricket, and knows enough about sport’s vicissitudes to resist citing a predetermined target as the end point to his playing days.

"I was just trying to get past Brett Lee and I'm even with him now, so you never know," Johnson said in response to the lure posed by Lillee’s mark that once stood as the pinnacle among Test bowlers.

"I could go a few Tests without wickets and that'd be the end of it.

"But it wouldn't be a bad thing - Brett was an idol to me and I remember saying when I first got into really serious cricket that I wanted to bowl as fast as Brett Lee..

"So now that I'm level with him (on 310 Test wickets) it's pretty awesome.

"I never thought I'd reach that target, especially a few years ago, I wouldn't have even thought (about) getting close to 300 wickets.

"But Dennis (Lillee), it's a pretty remarkable career that he had, playing (70) Tests and getting 355 wickets at low 20s (23.92).

"That's pretty awesome. I'm not sure - I'll have a crack, but if I get there or not, who knows."