The Blood of Dawnwalker gives you thirty days and thirty nights to reach your family before Brencis sacrifices them at his investiture. Almost everything written about the game before launch treated that as a countdown you race. It is more useful to treat it as a budget you allocate.
Eight segments, twice a day
Each day is divided into eight time segments, and so is each night. That is the unit the clock moves in. You do not lose a segment by existing, and you do not lose one by walking somewhere.
The game states the rule itself, in the manual entry it calls Time Progression: time progresses as you complete activities marked with an hourglass, and when all eight segments fill, day turns into night or night turns into day. If the hourglass is absent, the activity is free.
What carries the hourglass is plot: advancing a quest, and certain conversations. There is a third that catches people out, because the game mentions it somewhere else entirely. Learning advanced perks progresses time too, so your build is paid for out of the same budget as your story.
The game warns you before it takes one
This is the part missing from most accounts of the clock, and it is the answer to the complaint that segments vanish because you walked too near something. The manual says that some activities progress time without asking you to confirm, and that the Time Bar blinks when you approach one of them. It also says the blinking bar shows how many segments the activity will fill.
So you get both the warning and the price before you commit. What you do not get is that warning by default in every case, because it has a switch.
Turn the proximity warning on
On the Gameplay tab there is an option called Time-Progressing Activities Proximity Indicator. The game describes it as toggling whether it will warn you that you are about to walk into a time-progressing activity.
If you are planning a tight month, that is the most useful switch in the menu, and almost nobody arguing about the clock seems to know it is there.
What nobody can tell you yet
There is no published cost per quest, here or anywhere. The figure the blinking bar shows is decided while the game runs, and no shipped file holds a table of it, so every per-quest number you will read at the moment is an estimate rather than a reading.
We would rather say that than print a plausible number. When the costs are measured across a full run they will go on the quest pages themselves, which is where you are already looking.
Exploring costs you nothing
Climbing all eleven towers, clearing bandit camps, lighting shrines, following a will-o-the-wisp into a bog: none of it moves the clock. You can spend as long as you like filling in the map.
So the instinct to rush past the valley is exactly backwards. Rush the quests if you want more of them, but never rush the exploration, because it is not on the meter.
You cannot do everything, and that is deliberate
The story itself runs roughly seven to ten days. Filling the month with side content takes about twenty. The developers have said outright that a completionist cannot clear every side quest in a single run, and the game is built expecting you to make peace with that.
A full run lands somewhere between 55 and 70 hours, so the thirty days are not short. They are just finite.
Letting the clock run out is one of the seven endings
If the thirtieth day passes, you do not get a game over screen and you are not thrown back to a save. The investiture goes ahead, the sacrifice happens, and the game resolves into the ending it calls Time Runs Out.
Knowing that changes how the month feels. There is no failure state waiting to punish a slow player, which means the pressure you feel is the pressure you chose to feel.