In the NRL, there could be five head coaching changes on the horizon.

In the AFL, there's none - a rare tranquillity.

Since 1969 in the AFL, only twice has there been no head coaching change at a season's end - in 2003 and 2005.

Those snippets of history are set to repeat should St Kilda hold their nerve with Alan Richardson and Carlton stick their course with Brendon Bolton - with both clubs steadfast they will.

In contrast, the NRL's carnival of coaching change has names on the merry-go-round including Penrith's already-sacked Anthony Griffin, Brisbane's Wayne Bennett, Wests Tigers' Ivan Cleary, South Sydney's Anthony Seibold, St George Illawarra's Paul McGregor and Manly's Trent Barrett.

Sacking coaches isn't new in either of Australia's most popular football codes.

What is fresh is the AFL retaining status quo.

Why is it so? Simplistically, because of Richmond.

The Tigers' coach Damien Hardwick was considered a dead man walking after 2016 when his club finished 13th - that was his seventh season at the helm and he hadn't won a final.

But after an intense review of all aspects of the club, Richmond kept faith in Hardwick and he duly delivered the 2017 premiership.

Richmond's success came with a change in playing style rather than a change in coach - although five of Hardwick's assistants were let go at the end of 2016.

And in a competition where the also-rans invariably turn copy-cats of the pacesetters, a trend has started: back the coach, change the system.

Collingwood followed Richmond's blueprint: Magpies coach Nathan Buckley last year missed the finals for the fourth consecutive season in his six-year tenure.

He was widely expected to be marched but, like Richmond, the Magpies stuck by their coach. This season, they're finals bound and flag contenders.

"It's better the devil you know than the one you don't," Adelaide's inaugural captain Chris McDermott wrote in a column for News Corp this week.

"And change simply for change sake is rarely the best recipe for success.

"Richmond has proven it. Collingwood has followed suit."

But there's a ripple effect: assistant coaches are now, as McDermott puts it, the "new whipping boys ... disposable commodities".

Port Adelaide, St Kilda, Hawthorn, Gold Coast and West Coast are among clubs already confirming changes to assistant coaching staff for next season and others are expected to soon follow suit.

Australian Associated Press