I want to run a campaign where time is a central factor, in the sense that NPCs will be certain places at certain times, and learning these patterns is important, but I'm not sure how to handle it. In combat, I can use the "one turn is 6 seconds" rule, but how do I keep track of time elapsed while my players traipse around the town? While they talk to NPCs?
1 Simple task = 15 mins/.25 hours & 1 complex task = 1 hour
Crafting, training, and other more long term tasks are handled fairly well in the books with concrete requirements and values given for making a magic item or learning a new tool proficiency. The rules however fail to cover everything that happens between those 6 second combat rounds and the longer, day+ activities. My suggestion would be to use a rule of thumb where a simple task takes 15 minutes and a complex one takes 1 hour. This will encourage time management and multi-tasking by the party, but shouldn't be overly stingy or punishing.
Time × Speed = Distance
Handling time increments for travel is easy, every creature has a given speed and the rules show how to convert that to overland travel speed (including whether or not a PC is encumbered, and other factors). Break down the creature/pc's day speed into an hourly movement rate and you can easily represent/account for travel between districts in a large city or moving around the countryside in a small region without taxing the PCs too heavily.
I believe the easiest way to manage this in a way that is intuitive to both you and the players and that doesn't force you to keep a log book of minutes and seconds is this:
Draw a circle and color the top half yellow and the bottom half blue. Label the left side morning and the right side evening. Noon is obviously straight up and midnight straight down and I don't think you need to label that, but yellow and blue are good day and night colors. Put an arrow on it in the center to make it a dial. You don't even need numbers on it, because honestly unless someone in the adventure has a watch or a clock, accurate time is rather meaningless.
As your adventurers do some things, and as appropriate advance the dial a little bit. You don't even have to announce the advancement of time to the players. Just like in real life, sometimes if you aren't paying attention you suddenly discover it's afternoon when you thought it was still morning. Let the players pay attention to the "sun" dial as it were. If they go get something to eat at the inn, that probably takes up an hour or two without much necessarily happening other than a the players not being hungry anymore and a few gold pieces lighters.
Time tracking gets important to me in dungeon crawls to add to the reality of the situation. When my players began playing, they figured out that searching a room could net them treasure or a perception check that discovered secret doors if they looked at walls. Finding and disarming traps takes patience, so time passes. I use 5 or 10 minute intervals and general guidelines:
10 minutes to search a room (and ask them which aspect, walls, floor, the barrels, etc.)
5 minutes to disarm traps or pick a lock if proficient with thieves tools; 10 minutes otherwise. This assumes fairly straightforward mechanisms, not complex puzzles.
Too much disagreement at the table about which way to go, or what to do, or where to look = 10 minutes and random encounter check.
- 200 ft movement in a dungeon (slow) per 10 minutes. This allows characters to keep a simple map of where they are (if they want).
This leads to:
- torches or light spells blinking out.
- oil being used
- random encounter checks in dungeons at regular intervals
- Food consumption
I think the old AD&D DMG had much better definitions for these areas, I wish it was a little more defined in 5e, but this works :)
- Determine how long they take to go from one site to another
- Determine how long they'd take to realize a task (collecting informations in town could take from half an hour to two hours, finding someone to buy their magic item has its own rules in the DMG, reading all the equipment to leave town could take an hour)
- Do not allow much off-game talking unless it's necessary and keep track of for how long they argue about what to do
- Keep track of everything and add all together in the end
In the following example, they spend 3 hours and 15 minutes and they might have a 2 days long walk:
It's a 15 minutes walk till you find the tavern. You all drink there until the bard comes back and meet you, 2 hours later. He says that after asking around, he found out the tiefling you are looking for lives in a forest 50 miles always. It will take 2 days by feet to get there if nothing goes wrong. After that, the wizard leaves to buy magical components, he will take about an hour to accomplish this task, what do you do meanwhile?
It is quite simple, actually.
The secret to keep track in a easier way is to use numbers like: 15 minutes, 30 minutes, an hour (60 minutes) and so on. You don't have to be too hard on yourself calculating the distances inside towns. If the places are too close, say they can go and come back in 15 minutes. The fact you're always counting time will cause the atmosfere you want.
For D&D 5e directly, you can always go to the more complicated way and use what I said but carefully checking how fast the walking speed of your party is and how large the town is (besides, how far each part of the town is from where they are when they are moving).
Note, though, that it will make it a lot less fun to be always checking distances and calculating time in a more complicated way.