Clocks are for tracking progress, not time.
When you create a threat, if you have a vision of its future, give it a countdown clock. You can also add countdown clocks to threats you've already created.
Around the clock, note some things that'll happen:
- Before 9:00, that thing's coming, but preventable. What are the clues?
What are the triggers? What are the steps?
- Between 9:00 and 12:00, that thing is inevitable, but there's still time to
brace for impact. What signifies it?
- At 12:00, the threat gets its full, active expression. What is it?
As you play, advance the clocks, each at their own pace, by marking their
segments.
Countdown clocks are both descriptive and prescriptive. Descriptive:
when something you've listed happens, advance the clock to that point.
Prescriptive: when you advance the clock otherwise, it causes the things
you've listed. Furthermore, countdown clocks can be derailed: when
something happens that changes circumstances so that the countdown no
longer makes sense, just scribble it out.
-- "Threats: Countdown Clocks", Apocalypse World 2nd edition, p. 117
In practice, the "prescriptive" element of a clock is PC-facing - you give the PC a choice of prices to pay and one of them is "advance a clock". The overall model is detailed after the model of the doomsday clock. Three ticks take you 15 minutes to midnight, three ticks take you the rest of the way.
The larger concern is that when you create a clock you, as the MC, can both break the progression to the future of a threat into ticks to put on the clock and conceive of what it means for a clock to tick from one time to another. Blades in the Dark had clocks that were largely 4, 6, or 8 ticks long, but really you can have a clock of any size as long as you can genuinely say that you understand both the whole thing at once and any individual slice.
But are you tracking time, or fate?
The fundamental problem with putting anything on a time clock is that you have to expose time increments to the PCs in the way you would otherwise expose clock ticks. Even if you limit time increments to lengths anyone would call significant, an hour or more, well, there are over 15,000 hours in two years.
You might find some interesting inspiration for the thing you're trying to portray in Marshall Miller's 2015 The Warren, or Steve Wallace's 2016 No Country for Old Kobolds (NCOK). In both cases the players are taking on short-lived beings trying to do what they can for their society before they pass on - kobolds because they can only stand up to a hit or two, rabbits because their move list is their hit points and as they acquire scars from disasters they become genuinely incapable of certain things, letting the GM drive when they try to do them. Voluntarily leaving the troupe is an option for both, either in safety or in a blaze of glory.
"Before your fate catches up with you" can be much more understandable than "before your time runs out", especially because everybody's already assuming that these little creatures are going into the big, dangerous world to risk their lives for...
The society needs things urgently.
This is another feature of both The Warren and NCOK - when a creature drops out of the troupe, their replacement comes from that creature's common society, and a decent amount of the focus of play is on doing things to provide for that society. NCOK also dedicates a significant amount of page space to the things that a properly supplied society is capable of through collective action; in fact, the society is actually the thing that advances when individual kobolds gain experience in the field.
But ultimately, if you have a society with urgent needs, you have a good reason for any given PC to risk their lives to provide for those needs, and therefore for a PC's fate to catch up to them.
Even if you're not tracking time, can you track seasons?
Sure, but not really with a countdown clock, unless you have a real good idea for how to convince PCs to wait a month or something as a price to pay. If you want to just advance the seasons as you go through play in order to vary the landscape, you can keep a strictly descriptive clock and update it as part of your normal session-bracketing procedures.
Torchbearer does a simple step; every time you return to town from an adventure, the season advances, and you winter over in town. Mouse Guard gets a little more complicated with seasons which advance after a certain number of weather-based twists -- though winter is "longer" than most other seasons since mice are also expected to winter over in Lockhaven rather than risk themselves in the field, and a long winter gives the GM leeway to hit the patrolmice with storm after storm.
You might consider a seasonal clock with multiple slices per season, and make part of the end-of-session bookkeeping to determine how many slices to mark:
Then, your players consider the following questions about the events of the session. Mark a slice of the season clock for each "yes" answer:
- Did we go on a long journey?
- Was the weather a significant obstacle for us?
- Is the steading secure enough that we want time to pass?
