Right. The ship to the Island of Deadly Perils leaves without you. Rival adventurers get to the Lost City of Gold ahead of you. The hobgoblin outriders are reinforced with heavy infantry. The price on a needed commodity goes up. Parts of the dungeon are flooded with water or sand.But it doesn't have to be "an emergency," it just has to be a bit of time pressure.
My players learned that the temple of Heironeous in Greyhawk had a potion of supreme healing available, which they wanted -but they didn't have the means/funds to get it. They did however have an opportunity to acquire the funds, they pursued the opportunity.
The opportunity took them 5 days. I had privately determined that, after 3 (1d4+1) days (It's Greyahawk, lots of wealthy people), a 3rd party would buy the potion.
So when the players returned for it, it wasn't there - a bit of a loss. But they still had a boat load of gold and had gotten experience along the way - they weren't exactly crushed.
Not any kind of emergency, just a time pressure.
Yeah, I tend to use mild time-pressure a lot. Far more mild than the examples @iserith gives, actually - I would say most of those are close to "emergency" level time pressure, and you don't need to go as hard as that, and indeed, if your players "call your bluff" on some of that sort of thing (usually by accident!), it can lead to situations that are vexing and uninteresting for everyone ("the session where we spent two hours trying to arrange another ship to take us" is not likely to be a memorable favourite barring particularly spectacular inspiration from the DM). But, for example, the senators who you are escorting want to get to the fortress and safety as soon as possible, plus they're kind of annoying, so the adventurers don't want to draw things out. That keeps them only resting etc. when they have to.Time pressure? Often. Actual in-world deadlines? Approximately never.
I try to keep the world moving in places the PCs aren't, but I mostly don't bother thinking about what that movement is until/unless the PCs interact with it.
Right. The ship to the Island of Deadly Perils leaves without you. Rival adventurers get to the Lost City of Gold ahead of you. The hobgoblin outriders are reinforced with heavy infantry. The price on a needed commodity goes up. Parts of the dungeon are flooded with water or sand.
There are practically infinite ways to create time pressure in the context of a game based on make-believe. In the doing, it tends to create a sense of urgency and, as I mention above, gives more weight to the players' decisions.
I was going to say this as well. Occasionally, there is an actual ticking clock (you must rescue hostage by midnight or they are sacrificed).If ticking clock means there's a deadline - not very often. If ticking clock means things are happening in the background and reacting even if the PCs turtle up in their Leomund's tiny hut for a long rest - most of the time.