"The third season is fatal." So said the legendary Hungarian coach Bela Guttman. If a manager stays in post for longer, Guttman suggested, players get bored and opponents start figuring you out. It may be a shame he didn't live long enough to meet Paul Tisdale.

The man cited by Keith Curle as an example to follow amid Carlisle's poor form is approaching the end of his fourth supposedly fatal cycle at Exeter City. Still breathing after 11 years, Tisdale and his team sit at the top of League Two with 19 points from a possible 21.

The Grecians' well-turned-out manager is a known rarity, since only two other current bosses at this level have served more than four years. Curle hits the three-year mark next Tuesday and so hectic are reigns these days that such a short length of time still feels like a saga.

They do things differently in Devon, though, and while Tisdale is certainly a survivor, it cannot be denied that he has also been given an environment in which survival has been possible.

In 2013/14, for instance - the campaign Carlisle crashed back down into League Two - Exeter finished 16th in the bottom tier. The following season they lifted to 10th, but by 2015/16 they had settled back into lower mid-table, and 14th.

For many clubs - especially those who had spent three recent seasons in League One - that would have been enough. Thanks for your time, taken us as far as you can, fresh approach needed, etc etc. Tisdale, though, remained in post, and faith in his methods also earned him patience last winter, when the Grecians were at the bottom of League Two.

This is the period Curle referred to when facing questions on Carlisle's form this week. Exeter, of course, surged remarkably into the play-offs, where they beat Carlisle before falling to Blackpool, and Tisdale has since taken delivery of the first manager-of-the-month award of his career.

A body of work and a particular style at a supporter-owned club who have endured periods of financial difficulty, including transfer embargos, mark Tisdale out. Curle, having led United from a relegation fight to a play-off campaign in his much shorter tenure so far, feels he deserves a similarly even hand.

Can he expect it, though, if it takes longer to turn United around? They are 19th after seven games; one hopes this is as low as they go, and that Barnet today get the first blast of a backlash. But what if it gets worse before it gets better?

Would Carlisle accept the Tisdale principle in a similar situation, where a few months of poor results can be coped with because of a bigger picture?

Would their board? Would anyone?

One or two, yes. But not many. Some of the seething reaction to United's defeats at Accrington and Coventry have suggested supporter tolerance has its limits and, in light of poor form dating back to January, the question may also be whether the bigger picture in Carlisle's own case would be enough for those at the top of the club.

What has been built at Brunton Park since 2014? What values are in place and worth more than a string of draws and defeats?

Certainly, Curle has changed the feel of the club's internal workings, putting clearer dividing lines between departments and, it is said, establishing a more professional environment throughout.

A certain playing style is at times visible, and often discussed, while Curle also, from time to time, talks in terms of making United think bigger: demanding more investment, making occasional comments about the club's ambition (such as post-Exeter in May) that come across as a challenge to those steering the ship.

That mindset is what the manager has attempted to lay in place and those are not necessarily intentions that should be discarded. The accent, meanwhile, has been and remains firmly on the first team, Curle believing that expanding the club's core of younger professionals would only be beneficial should United rise through the leagues and grow accordingly.

Hence, at present, an awkward "development squad" project, involving just four teenagers, which has the feel of a club initiative rather than the manager's own scheme, given that none has been tested in a first-team game yet this season, and two are now on loan in the Northern Premier League.

And it is understandable that a boss would go this way - to try and nail the senior stuff before thinking of deeper ideas. In his short United reign, Graham Kavanagh gave generously of his time to explain his philosophy for the Blues in these pages. It was a perfectly reasonable and decently-offered set of thoughts, yet a few months later, first-team results saw him ejected.

We did not get the chance to learn whether Kavanagh could have presided over a club that became dynamic in finding and nurturing young players, like Tisdale has with such as Ollie Watkins and Matt Grimes. Curle, right now, appears to have shorter-term priorities.

He presumably knows, in reality, that there are few Tisdales for a reason, few Exeters for that matter, and not many clubs that tolerate a patch of failure for ever. It probably pays, in that case, to keep the wider concerns to a minimum.

It is a front-loaded philosophy shared by many, yet when it goes wrong, it usually has to be put right quickly if a boss isn't to find himself in peril.

If Curle is still the board's man for the long-term, and results either way would not alter that, one imagines there would be ways of reassuring him and explaining as much to the rest of us in due course. There are certain things, meanwhile, that he can more easily sidestep, such as criticism of his touchline style by the former striker Stephen Elliott.

That style achieved safety and then improvement, and those players "slagging off" the manager behind his back in 2014/15 did not necessarily do so from a moral high ground where performance was concerned.

He may also invite us to study the list of long-serving managers and observe that, of all those directly above and around him (Curle is 10th in the EFL), there isn't one who you'd say didn't deserve a decent amount of respect for the job they've done at their respective clubs.

It would be fair to say that some of those names have also had to manage their way out of the odd crisis, and under more orthodox pressure than Tisdale routinely finds, too. As his three-year anniversary approaches, there is certainly a case for Curle to deserve the same sort of chance. But take it he must - and the sooner, the better.