But is this going on every day? And if you are relying on the mere possibility, how hair-trigger do you expect the PCs to be? Are they really to live every day - and the players to play as if - every day may be the outbreak of WW1?
I'm happy to drive play through frenetic action, but I'm not sure I would want to try and drive it through what (if I've understood it right) seems to me to be a type of frenetic anticipation.
But where are they on the days that it
matters? It is the possibility that any particular day
may matter that keeps them moving, and the certainty that if they waste enough time then they
will fail.
So my PCs don't risk the consequences of a 15 MAD - they know that I
will allow them to fail
Even more annoying sometimes is when somebody
else does the deed of daring do - when the PCs discover the bad guys crucified to the wall, and a biblical passage scrawled in their blood. (That happened in a Vampire game once - the PCs told somebody what the bad guys were up to, but then didn't
do anything about it. The person that they told was not so faint hearted. He was also a sociopath....)
Time may not
always matter, but to make a blanket statement that time
never matters, and never
did is about as false as possible, I would call it codswallop and nonsense, but then I run steampunk games.
Something major may not happen every day, but there are indeed *BAM* episodes, and if those days happen while the PCs are off licking their wounds.... Whoops, WWI has just started, so sorry guys, but this is now your fault.
Most episodes are just episodes - they advance the plot,
and provide clues. Others are crucial, and can change the course of the game.
In honesty I would describe my games as involving one part of information gathering for every two or three parts action. My models is more Tinker, Tailor, Soldier, Spy than Mission: Impossible. Though I could describe it as more Mission: Impossible (original) than Mission: Impossible (Cruise crap) - investigation and the working out of schedules was important in the original.
This is also why I call the 15 MAD lazy - the party is wasting time, and time
will keep ticking. They have decided that their convenience is more important than what is going on in the world.
Nap time!
The PCs are important, it is why I may put them in Sarajevo, but time marches on without them.
Let us say I put them down in the area about a month before the Archduke is shot? If they confront part of the Black Hand, use their spells in a mad Nova (remember, the Black Hand was largely a 'conspiracy of clerks' - not skilled assassins) to take down the ones in the beer hall basement,
then rest the remaining few will relocate, and perhaps push their agenda forwards (or back) a few days. (What, you don't remember the AustroHungarians having fireballs?

)
Time matters.
And not just in major things - every day wasted
could be a day wasted. Opportunities
might be missed. No guarantees either way.

The thing is that the PCs don't know which days are important and which is not.
Sometimes days can pass when nothing happens, sometimes it is just an opportunity to gather information from the courier that is going to be in town for one night, then leave in the morning. Sometimes it is just the villain's henchmen come into town to get supplies. And sometimes it is just a matter of knowing the tides, and when the sea caves down the coast can be entered.
Other days something major happens - be it an attack on the town, the Archduke getting gunned down, or the necromancer awakening the lich under the barrow downs.
For a sandbox setting I cheat - time starts when the PCs reach an area. So, in my Fallout game, time in Gibsonton, Florida didn't really start until the PCs found a loose two trunked elephant, and tried to figure out what to do with it.
In this instance they took it back towards town, getting them in good with the Freakshow that owned it, which led to them helping protect the town from Raiders, which led to.... Time is passing in Gibtown
now but I waited 'til the PCs arrived.
They have noticed that the super mutants, including the behemoth, will start getting agitated, then get a faraway look in their eyes and calm down.
They have noted several important townsfolk, including some Romany, getting that same faraway look, then change the direction of their conversation.
The overall plotline for the town involves a mind controlling mutant, similar to The Master... He is using his power to help calm the super mutants, and really wants to get the circus rolling before he dies in a bit less (or a bit more, depending on the PCs) than a year. DC style super mutants, The Ringmaster's influence allows them to think without pain. He mostly just talks to the townies, and only 'controls' the super mutants only to keep them from going into rages.
Unlike The Master in the old Fallout game, he is not one of the bad guys.
Likewise, the timeline for the Darkened Tunnels does not begin until the PCs reach Disneyworld, and meet ghoul/paladin Ethan Sparkes.
On the other hand Henry P. LaTota has an agenda based on certain astrological occurrences (Solstice, Equinox, Cross Quarter) - a lot of times the PCs
won't be in a position to stop him, but will hear about what happened later. (He is the Big Bad for the campaign. AKA The Royal Pant, Randolph Flagg, the Herald of the End Time, and perhaps to become known as Holy Crap - it's Nyarlathotep!
Run!)
The PCs may never realize that he is a direct counterpoint to The Lone Wanderer from Vault 101 and Harold, the Man in the Tree. The characters in Fallout 3 started the world toward healing, Henry P. LaTota is turning it toward destruction.
His timeline occupies a bit more than a year, and his clock began ticking the day the PCs began their travels from Vault 415. They will meet him for the first time (though they have seen him at a distance before) on Friday. Urbane and charming he will be in the role of tempter, this time.
I rather suspect that they will hate him right off the bat, no matter how silver tongued he might be. Gibtown is a town of freaks, mutants, gypsies, and oddities, and looks to be shaping up to become their home base. He is representing two groups known as The Skins and The Kreiger - neo-Nazis....
The Auld Grump