You started the summer in the Test team and have finished it retired from both international and state cricket. At the back of your mind, did you have any inkling this could be your last season?
All through my international career I knew that I had to continue to play very well to keep my spot, at my age. I knew there was always a possibility of one or two bad Test matches and that could have been it, which is the way it ended up panning out. But I guess at the start of the summer I thought that if I was able to make it through the entirety of the Australian summer I would look at things then. Unfortunately it didn't quite work out that way.

Why the decision to also retire from state cricket?
I just think it was time. Sometimes you just know. Not having that carrot of playing international cricket anymore was one factor. The fact that I probably didn't finish the season in the best of form was another factor. Sometimes you just know it's time to move on and give an opportunity to others.

Now that your international career is over, how do you reflect on what you achieved? You must have thought that, getting to 35 without a baggy green, it realistically wasn't going to happen?
One hundred per cent. Well, maybe not 100%. Maybe there was a brief hope fluttering at the back of my mind somewhere after seeing Chris Rogers get picked at a later age, and Mike Hussey before him. So maybe all hope wasn't gone, but the older you get, that hope fades away a little bit. The thing I'm most proud about is that I really had to earn that opportunity through a heavy weight of runs in Shield cricket. I was able to have a big domestic season, and Western Australia and the Scorchers had success in that season as well. To earn that opportunity to get a baggy green at 35, and then to have three terrific years of international cricket - sure, there were a couple of downtimes during that period - I certainly loved every minute of it.

You've retired with a Test batting average of 61.87. Surely that sort of record was beyond your wildest dreams?
Exactly. If you'd told me a few years ago I'd get the chance to play 20 Tests and end up with an average of 61, I would have taken it every day of the week. I had a terrific time playing international cricket. I got picked at the right time, and sometimes that timing is everything. I was in good form, I was really confident, I knew my game really well. And I was in a purple patch that lasted for a fair time. I certainly enjoyed every bit of it.

"The thing I'm most proud about is that I really had to earn the opportunity through a heavy weight of runs in Shield cricket"

That 2014-15 Shield season you mentioned - it was 1358 runs, which is the fourth highest Shield tally ever. You were 35 but were you only just peaking?
I think everyone peaks at different ages, and mine just happened to come a little bit later. I've got no doubt that the influence of Justin Langer coming back and coaching Western Australia coincided with a change in my form and fortunes. But thinking back on that season when I scored the 1300 runs, I was just confident. I just felt that every time I went out to bat, I was ready to make runs. I guess I stayed really hungry, so that if I did get to 50 or 60, I went on to 100. And if I got to 100, I made sure I went on and got a big hundred. It was that hunger for runs that drove me to have such a good year.

You mention the influence of Justin Langer, but at 35 you must have known your own game extremely well. What could someone like JL have done to help lift you to an even higher level?
He came in and took me back out of my comfort zone. Maybe I'd slipped into that a little bit in previous years. Having played cricket for a long time, maybe I wasn't working as hard. The way I worked and the effort that I put in certainly went up a couple of notches under JL. We changed a couple of technical things, and he just worked me incredibly hard - and our whole squad incredibly hard. He's had a huge impact in the cultural change that's happened in Western Australia over his time. I've got no doubt he was able to take my game to another level.

And a hundred on debut - and being the oldest man ever to score a hundred on Test debut - is that your best memory of international cricket?
Yeah, I think so. All my hundreds are special and unique in their own way. The situation of the game was that we were in a little bit of trouble, so to be able to bat with the tail and put on a few handy partnerships, which ultimately gave us a pretty handy lead and helped us win the Test match - that's one of the biggest highlights.

You finished up averaging 542.00 against West Indies. What was it about their attack that you liked so much?
I think it was just timing. We played on some really good batting wickets. I was playing as well as I could play at the time. Often I was coming it at 3 for 300 or something, so I was getting to face some pretty tired bowlers. It was a period of time where everything seemed to click. I'd like to think that if it was against any other opposition, hopefully the results would have been pretty similar.

What about the Wellington Test last year? You were bowled for 7 off a Doug Bracewell no-ball that proved to be an umpiring error, and then went on to make 239.
For all the times I thought I'd got a bit of bad luck, I think it all got made up for in that one moment! I still had to come out and score the runs the next day. But that one moment of luck - and that's exactly what it was - changed the whole course of my innings and ended up changing the course of that game. I still remember Tim Southee talking to the umpire at the time and saying, "Well, as long he doesn't go on and get a double-hundred, I'll forgive you."

After such success in the 2015-16 summer, can you pinpoint what went wrong for you on the tour of Sri Lanka last year?
The Sri Lankan one was a really disappointing one. I went into that series really confident about my plans and how I was going to approach batting in the subcontinent. I'd toured a few times with Australia A squads and Centre of Excellence squads, so I'd had some experience in the conditions. I had a really good plan about looking to sweep spin and had worked incredibly hard on it prior to that series, and I was basing a lot of my game around that. But my first practice game I got out sweeping both times, and I just started to second-guess myself a little bit. I know that's where I went wrong. If I had my time again, I would have just stuck to my guns and stuck to my plan. Whether it would have changed how I would have played, I don't know, but that was one thing that on reflection I was disappointed that I started to second-guess my game plan a little bit. As soon as I did that, things became harder.

From watching the recent series in India, what did you sense made Australia more competitive than in Sri Lanka last year?
You could just see the guys were a lot more well equipped. They were better organised, they knew how they were going about their plans. It was markedly different. I know they didn't get the series win, but I thought the team played exceptionally well - sitting at home on my couch watching it. The team has certainly taken some big strides forward.

Your international career finished in an unusual way - unavailable for the Adelaide Test after being concussed in a Sheffield Shield game. How do you reflect on that ending now, a few months later?
That was a pretty tough time, to be honest. The scrutiny going into the Hobart Test, then the performance in the Hobart Test and the backlash that came out of it, was an incredibly tough time. Then to be on a plane and batting two days later and cop one in the head, all in the space of a week or so, it took a fair bit out of me - probably a bit more than I was willing to admit at the time. I had a little bit of time off after that; maybe I should have had a little bit more time off. But I was always keen to get back out there and get playing as soon as possible. I've got no doubt that played a big part in my thoughts about retirement. That's where they first started.

"I had a really good plan about looking to sweep spin and had worked incredibly hard on it. But my first practice game [in Sri Lanka] I got out sweeping both times, and I just started to second-guess myself a little bit. I know that's where I went wrong"

What are your memories of the concussion against Tasmania?
It got me well, and I'd copped one in the back of the head fielding for Middlesex a couple of months previous. It's amazing, I went through a whole career without having any dramas and then suffered two pretty significant concussions within six months of each other. It was one of those things, it just takes you a little bit of time to recover from. Physically, you'll always recover, but mentally getting back out there and getting back into facing short balls - I had to do a lot of work around that before I felt ready to go out and play my next game. To go through that process and make sure you're confident enough to go out and face the next ball that gets delivered to you, takes a little bit of courage.

Should concussion subs be part of the game in all formats?
Yeah, 100%. I'm a big believer in concussion subs. That game against Tasmania when I did get hit, I rocked up to the ground on day four and thought, if I get a chance to bat in the second innings I'll put my hand up. But I'd already been ruled out by medicos, who ultimately take the decision out of your hands. And I think once that happens, where as a player the decision gets taken out of your hands, I do believe that a substitute is the right way to go.

You played in a couple of Sheffield Shield finals but never won a title. Is that the one achievement you really wish you'd managed but didn't?
Yeah it is. I would have loved to have won a Sheffield Shield. For me, it's still the pinnacle of Australian domestic cricket. I was lucky enough to have played in a couple of Shield finals and we got a couple of away draws, which wasn't enough. I'm incredibly lucky and proud to have achieved what I have achieved, but if I could have chucked a Sheffield Shield title in there, it would have probably completed it.

How does the Shield compare now to when you started? Is the competition as tough?
It's an interesting one. I see it through different eyes now to 15 years ago, when I was first starting. Everything seemed a lot tougher back then. But I'm not sure that the standard has dropped at all. Maybe you don't see young guys pumping out 1000-run plus seasons, like I saw when I first started in the game. And maybe guys are getting opportunities without having to score an absolute mountain of runs, but I think it's very cyclical in that way. I still think the Shield is a strong competition. I think the advent of T20 cricket has certainly increased the pace the game is played at these days. You don't see too many draws anymore in Shield games. There are often results, and those results often come on day three. We even had a two-day game this year against Victoria. That's been one of the biggest changes that I've seen, but I don't think the standard has dropped in any considerable way.

The national selectors always have the challenge of balancing youth and experience - do you think the way your career panned out is a reminder that players over 30 shouldn't be forgotten about and often have a lot to offer?
No doubt. You'd like to think that everyone who's playing Shield cricket, regardless of their age, if they're playing well enough should be given the opportunity to play for Australia. Because that's what keeps driving a lot of people, it's what keeps motivating people. It's important to have those experienced heads in and around Shield cricket. I remember when I debuted, I was a youngster amongst a lot of senior heads. Maybe the dynamic of a lot of teams has changed these days, where there are probably a lot more younger guys with a handful of older guys around them. But they're incredibly important for the development of the young players, to help them learn about their own game and help fast-track their development. But these guys need that carrot as well, that if they are playing well enough, hopefully international opportunity is there. And I think it is. You look at Michael Klinger getting an opportunity to play for Australia in the T20 format this year. I think it would have been a crime if he'd gone through his whole career, with the amount of runs he's scored, and not represented Australia in any format. I was extremely pleased to see him get picked this summer.

You have finished your career second only to Don Bradman on the list of Test averages (with a 20-Test minimum). How does it feel to see your name in that sort of company?
I've always felt uncomfortable with any of the comparisons. I've been flattered by them, but it's never sat comfortably with me. Donald Bradman and these sort of guys were absolute legends of the game. Numbers-wise, I'm really happy what I finished with, but I certainly don't put myself in that category.

What does the cricket future hold for you now?
I have retired from Western Australian cricket, but it's certainly not the end of all cricket for me. I'm heading over to England in a week's time to join up with Middlesex, which is something I'm really looking forward to. And hopefully I can go around with the Scorchers again. We've had some terrific success over the past five or six seasons. The idea of playing with the Scorchers, perhaps at the new stadium in Perth, is something I'm quite excited about doing.

Brydon Coverdale is an assistant editor at ESPNcricinfo. @brydoncoverdale