Former Australia coach Darren Lehmann has conceded he may have overstayed his welcome as chief mentor of the national team, signing two contract extensions before quitting amid the disgrace of the Newlands ball-tampering scandal earlier this year.

"I look back now and I had a fantastic five years coaching Australia," Lehmann told FIVEaa radio. "But I look back now and go 'maybe it was a bit too long' to be fair. I speak to Justin Langer quite regularly just making sure he gets some time off where he can because you're on the road and it's 300 days of high pressure trying to win every game. That takes its toll.

"It's 24-7, you don't sleep. You're thinking about either the day, the coming day, six months ahead, who you've got coming up, what players are coming back from injuries, you're talking to everyone. It's literally the most demanding job I've ever had, but it's great fun. Even right to the end I loved it.

Originally signing on in mid-2013 on a three-year deal to take him through to 2016, Lehmann was handed two extensions by the team performance manager Pat Howard, the first taking him through to 2017 and then the second extending his tenure until the end of the 2019 Ashes series in England - this last addition announced during a poor tour of Sri Lanka in 2016.

Initially, Lehmann had been seen as a short-term fix to problems in the national side under his predecessor Mickey Arthur, including the "homework" suspensions of four players in India in 2013 and a series of behavioural issues with David Warner, and the coach himself always insisted he was not in the job for the long-term. However a broadly successful early tenure, featuring the 2013-14 Ashes whitewash, a home series win over India in the wake of the death of Phillip Hughes and victory in the World Cup at home, meant Lehmann's time in the job expanded.

He was forced to resign at the same time Warner, Steven Smith and Cameron Bancroft were banned for premeditated ball-tampering and the subsequent damage to the image of the game.

"I was in a bad place like everyone for a little bit of time. It's taken me the last three months, I'm starting to feel a bit more normal and enjoying watching the cricket again," Lehmann said. "Your kids, and when your wife's copping it you say enough's enough. That's when it gets too personal and you take a step back."

In Gideon Haigh's recently released book, Crossing the Line, it is reported that there were concerns within the national team about Lehmann's health and ability to cope with the demands of the job as early as 2015. In January 2016, Lehmann suffered a serious deep vein thrombosis that forced him to take a break, leading to Langer stepping in as ODI coach for a Caribbean triangular series later that year.

"He was loath at first to take selectorial responsibilities, which 'had the potential to create friction between the players and myself': Howard needed to persuade him," Haigh wrote. "Nor did he see himself staying overlong, liking to quote his wife Andrea's question when he was offered the job: 'Do you think you can make a diference?' But Lehmann did stay. In a sense, he had to. Cricket coaching is a precarious occupation. The national role is the only one in Australia paid anything like a football coach; the position's prestige and perquisites are unmatched.

"In hindsight, some felt Lehmann should have moved on after the 2015 World Cup, by which time he was clearly feeling the pressure of indifferent health and prolonged separations from home. But with the retirements of Clarke, Haddin, Rogers, Harris, Johnson and Watson in short order, following the tragedy of Phillip Hughes, the coach's continuity appeared welcome. His influence was then consolidated by the need for the team's remaking under Smith and Warner, suddenly senior players despite their relative inexperience. As the coach was getting older, the players were growing younger. More and more he referred to them as "kids"--"good", "great", "hard-working" etc--when they might be men in their mid-20s or even older."

On the topic of the banned Smith and Warner, Lehmann said the ex-leadership duo were still feeling their way back from the traumas of earlier this year. "They're not too bad, they have good days and bad days like everyone," he said. "Obviously that was a pretty big mistake by everyone, but the game moves forward, and they're going ok, they're good young men, and they'll come back playing really good cricket for Australia."

Lehmann also spoke about Usman Khawaja, after his match-saving performance in Dubai. "Outstanding effort and probably puts a few knockers to bed," Lehmann said. "I think opening suits him in the subcontinent, he's against the new ball, it's not spinning as much... His record as an opener's unbelievable, he's only done it a few times and he's got two hundreds. I think he said it in his press conference where everyone said he's too lazy-looking if you like, but he's not like that at all.

"When he's training, he's training as hard as anyone else to be the best he can be, and trying to improve his game, and when he fails it hurts him like everyone else. He just keeps a lot in, but when you're inside the tent, you see those emotions come out behind closed doors."