A LITTLE over four years in the hot-seat, managing the club you have always supported, dealing with internal politics and a culture of selling players, torn between the demands of home and Europe and finding it ever more difficult to ignore the voice inside your head that is telling you to give the whole lot up and walk away.
For Neil Lennon in 2014, read Alex McLeish in early 2006.
There are clear differences between both situations, of course. Lennon had become just the fourth Celtic manager to win three consecutive championships but now desires a new challenge with all roads leading to England. He leaves Parkhead on a relative high.
McLeish had the hollow-cheeked spectre of Paul Le Guen hanging over him when the Scot announced at the start of February that he would be "standing down" at the end of a disappointing 2005/2006 season, but the deal was done only after he had been talked out of leaving the club there and then.
McLeish was exhausted, worn down, feeling like a failure despite having won seven trophies. A job at the Old Firm, as with so many men before him, had taken a heavy toll.
What the cases of Lennon and McLeish appear to prove when taken together is that there is only a very finite time, even in these days of the SPFL Premiership being a one-horse race, in which any individual can handle the intensity of life at the helm of one of Scotland's big two clubs. It is perhaps no coincidence Gordon Strachan only lasted four seasons at Celtic and Walter Smith bowed out after four-and-a-half years second time around across the city.
McLeish, who went on to have spells at Birmingham City and Aston Villa after re-establishing his reputation with the Scotland national team, understands, wholeheartedly, why Lennon wants to leave Celtic Park behind and test himself south of the border.
Ibrox was once Big Eck's field of dreams, the manager's office his playground. What the benefit of hindsight permits us is the chance to regard his time there, following the high-spending era of Dick Advocaat, as the beginning of the club's catastrophic financial problems cracking through the public facade.
McLeish had cost-cutting and its attendant problems to deal with and knows all too well how political strife, the relentless need to win every week and the stifling nature of public life in Scotland's second city can bring totems crashing.
Cash is no longer as plentiful at Celtic as it once was. Lennon is part of a business that buys players at a low price aiming to sell high, while still expecting a modicum of success in Europe.
The Northern Irishman would have greater resources to play with in England and a competition, whether that be the Barclays Premier League or the Sky Bet Championship, which would really allow him to measure himself as a coach from week to week.
"I know Neil well," said McLeish. "We don't go out for a pint every week, but he's a really engaging guy and I understand his thinking. It is hard to walk away from a job like that at Celtic and, reading between the lines, he has obviously become frustrated.
"There are shelf-lives nowadays. I was at Rangers for four-and-a-half years and Neil has been pretty similar at Celtic. It is difficult to see anyone staying at those clubs for 20-odd years now.
"At the time I was at Rangers, I really did think I was at the pinnacle. I was managing big players, we were in the Champions League and we only started to realise the bubble was bursting when the finances started to dwindle. That caused you to look at the future with a different perspective.
"I am not sure how Neil will be feeling, but there was a bit of relief for me when I finally left. I wanted to have a holiday, get some Vitamin D in the body and clear the head because there are times in these jobs where you can't see the wood for the trees. I came back recharged.
"I saw what my friend Davie Moyes experienced at Manchester United. Naturally, United were playing in a different country, but United and Rangers are massive clubs and I had real empathy with him because he was expected to win every single week. I knew all about that kind of pressure from my time at Ibrox.
"It is a massive rivalry that exists in Glasgow and it can become suffocating. Those jobs overshadow everything in your life. David [Murray, the former Rangers chairman] and I shook hands in the January, I think, when we had qualified for the last 16 of the Champions League.
"I was hinting, because I was so drained at that stage with five months of the season left, that I thought it might be better to go then, but he wanted me to lead the team out against Villarreal and I agreed to stay until the end of the campaign. I felt liberated when the statement was made, though.
"Neil will feel he has had his time and be ready for a new challenge. He has played in the Premier League. As a coach, you would want to manage there or work your way up through the divisions."
Like McLeish, Lennon has enjoyed the rarefied air of the knock-out stages of the Champions League. He took Celtic there two seasons ago, losing out to Juventus in the last 16, but found his depleted squad incapable of rising to the challenge during the last campaign.
There was a clear gulf in quality there. Suggestions persist that Lennon felt he could not do any more at that level with the financial model now in place at the club. McLeish is clear when asked how the current budgets affect Scottish teams trying to be competitive in European football.
"It is impossible," he stated. "Rangers and Celtic would need to get an oligarch in and, even then, UEFA's financial fair play rules would now make sure it didn't happen.
"The financial situation has never been as bad as it is right now in Scotland. Celtic are getting more Champions League money with Rangers not being involved at that level, but they need Rangers.
"I remember going through a period at Rangers where we had to put a plan in place to sell players and reduce wages by millions of pounds. We were all hurting at the time. It is why I wouldn't be critical of the people currently in at Rangers. It is hard."
Again, McLeish and Lennon share the unique knowledge gleaned from having managed the club they followed as children. Lennon wore his heart on his sleeve throughout and was loved by the supporters.
McLeish's public persona was somewhat cooler. His ambitions and emotions were intertwined just as tightly, though, and he can never quite forget the gnawing sensation that he had failed when he left Ibrox for the final time.
"I took my conscientious approach from my da', it was in my genes," he said. "He was a Govan shipbuilder's man and used to come home and talk about his work all the time. I took that into my own personality. I don't know if the right word is 'guilty', but I felt bad that I wasn't able to be doing better domestically. Part of me felt a failure because I didn't win a domestic trophy in the last year."
Time is a great healer, though, and McLeish has learned to cherish the memories of his time at the club he loved. "I've been to some Rangers dinners and the reception I have received has been overwhelming," he said. "I can say that managing Rangers was living a dream."