No discussion of the prospects of any AFL team beyond Victoria is thorough if it doesn't pay attention to the travel factor - especially the two teams out of Western Australia, whose fortnightly plane trips of usually four hours or more over a period of time become a sizeable challenge.
That's something rarely given enough consideration by "eastern staters", as people from Perth are inclined to refer to anyone living the other side of the Nullarbor Plain.
Few teams in domestic sporting competitions around the world have to make as long a trips as regularly as do West Coast and Fremantle.
It makes the Eagles' sustained success, seven grand final appearances and four AFL premierships over 35 years, a pretty remarkable effort.
But it's taken a toll on the length of the careers of some of the club's greatest players over that time.
It's taken a toll on some Eagles' line-ups which were good enough but unable to win flags.
And, at times like these, you can't help but also wonder if it continues to take a toll on the psyche of an entire club.
While Fremantle is in the same boat, it has only once - in 2013 - threatened in premiership terms.
West Coast's record in recent times makes it a particularly pertinent case study.
Adam Simpson, in his eighth season as coach of the Eagles, has an impressive record: 111 wins, 60 losses, one draw and a winning percentage of nearly 65; West Coast playing finals in each of the last six seasons.
The Eagles have won more than 77 per cent of home games at Subiaco and then Optus Stadium under his watch.
Their away strike rate of just over 50 per cent, given the extent of the travel imposition, is at worst fair.
But even winning a premiership in 2018, a year in which West Coast managed to win eight of 11 games outside Western Australia, doesn't seem to have made the Eagles any more adept at handling "the road".
Indeed, their record away from home since the premiership has got steadily worse.
That 8-3 road record (a 72 per cent strike rate) from 2018 became 6-5 (54 per cent) in 2019.
Last year when, thanks to COVID, West Coast played eight of its 10 games away from Perth against an opponent also from a state different to the game venue, it still went only 50-50. And this season, the record is just one victory in five attempts.
At the same time, West Coast has become harder to beat at home.
Since the 2018 premiership, the Eagles have won 22 of 27 games at Optus Stadium.
So, in five seasons leading up to the 2018 premiership under Simpson, West Coast went at a winning percentage of 65 per cent for home games and 53 per cent away.
Since the flag, it's been 81 per cent at home and 46 per cent away.
Given that the Eagles have had arguably just as strong a list since the premiership year, I suspect those numbers suggest that, increasingly for West Coast, it's about mindset.
This is a side which knows its capabilities, and has experienced the ultimate playing to its peak.
It knows it has a substantial advantage playing an interstate team at home and is likely to win far more of those games.
Counting the away clash with Fremantle, that's a dozen games in which the Eagles will almost inevitably start a warm favourite.
Win even three-quarters of them, and they know they need just four wins from the other 10 away to be reasonably confident of playing finals.
It doesn't necessarily mean they can pick and choose when to have a serious crack, but it does mean losing the most difficult of those away assignments, like Geelong at Geelong, for example, isn't really the end of the world.
And that's certainly what it looked like in Round 6 at the Cattery, when the Eagles were belted by 97 points, conceding a run of 13 consecutive Geelong goals, and 19 of 20 after a decent first quarter.
It's a theory which also sits comfortably with West Coast's repeated fade-outs this season; the Eagles conceding 71 points more in final terms than they've scored and their over-reliance on an admittedly very efficient forward set-up.
The latter factor certainly was pivotal to the Eagles' five-goal lead on Essendon early last Saturday night, despite the Bombers having their share of the football as well.
It was when the Dons' harder edge began to be converted on the scoreboard West Coast found itself in big trouble.
And when that starts happening at home as well as away, that's cause for major concern.
The Eagles found an extra gear when they won that famous 2018 grand final - in fact right through that finals series, winning the hard ball categories they had usually been beaten throughout that season.
That level of hardness hasn't been found consistently since.
That deficiency is telling against the very best sides in the AFL, among which on the score of talent alone West Coast should be perceived.
And while it remains absent, maybe too many Eagles luxuriating in what remains a substantial edge in their own backyard, things aren't likely to improve when they step on to another aeroplane.