Back in 2016, I wrote a post arguing in favor of shifting the resource model in wilderness adventuring towards that of the dungeon adventure, with spells recovered only in civilization. I'm still not sure that that's wrong, but I have come to look at a piece of evidence that I used there in a slightly different light.
I noted that parties on foot were likely to have only one or two random encounter rolls per day, with less than one encounter per day in expectation, and consequently parties will tend to have full spells almost every encounter. I have several new observations on this:
One: While this is true of ACKS, where
entering a new hex triggers a random encounter roll, it isn't true of
B/X (as represented by OSE) or OD&D. In both of these, you only get one encounter roll per day by default. Not sure about AD&D. But in OD&D and B/X, parties on foot and mounted parties get the same number of encounters per day (less than one in expectation), and if you choose to interpret OD&D's spell recovery the way that most people do, this means you're at full spells every encounter there too.
In ACKS, this might be viewed as a "circuit breaker" or comeback
mechanic, where a party which is too poor to afford horses, or which has
had its horses lost, stolen, or eaten, experiences a lower rate of
encounters per day and is consequently more likely to survive. Similar
to how the wilderness evasion rules favor small parties, to make
wilderness encounters survivable (but not winnable) for low-level
characters who cannot yet afford mercenaries; if you just hit 5th and only have one fireball per day, you can still do wilderness adventures, you just have to take them slow and cautious.
Three: If going slow
makes the resource situation easier, then hopefully it's a choice which should have
tradeoffs. The obvious resource being spent here is time. Rations and
starvation in ACKS are pretty forgiving.
So the main way time is expensive, outside factors like NPCs acting /
clocks ticking, is costs-over-time of mercenaries, henchmen, and cost of
living. But linking in-game time to out-of-game time
seems like it too would heavily discourage overly slow, cautious travel... and I don't know that the bookkeeping would be any
more onerous, really.