Is there anything timed/missable ?

[Buurt]

I kinda wanna take my time and play like "IRL" just chill, doing quest when I want to etc.
do I miss out of timed story things or other stuff if I just play how I want or will I be fine ?

[Rumpelcrutchskin]

Some quests have time limit and some don`t. You can advance the main story pretty much at your own pace and when you want to.

[MegaMan]

When you get a mission, go to the mission screen on the pause menu and look for a time limit. If it's a main story mission, chances are there is no time limit.

[Endora]

The only story mission that have a time limit is to repair the train window - if you don't do it, Mi-An will do next day. Just have 10 pieces of glass ready on your storage and it will be easy. The rest you can stall as much as you want.
Some Blue Missions have time limit too, but if you fail them there is no story consequences. As I remember, the most misseable is Pen's, just don't take his mission before you can craft Tempered Glass (need a Furnace lvl 2) - I don't like him that much, so it's easy do not be so friendly that the quest could trigger early.

[Bmm113]

it'll show a time limit at the bottom of the screen when you go to that mission on the missions tab. usually the commissions on the board will be timed, but they're also pretty forgiving if you cancel.

[Hentaika]

So since nobody gave a good answer - I thought it deserves an actually correct answer.
LOADS of things are missable.

Here are most of the missables, but I might have forgotten something:
1) Max permanent stamina via Cooper dialogues - there are at least 3 or 4 dialogues where you can continue listening to cooper to gain more max stamina.
IIRC there is at least one more such obscure 'max' something bonus not related to Cooper but I forgot what it was.

2) One missable accessory if you don't date Pen(gotta use the dating item since Pen has no auto romance quest) before he is removed from the game
The quest for this item also has a very nasty bug(that might get fixed later) - it leads to a cave between approx ranch and moisture farm that you might have already seen with level 50 monsters. If you already killed monsters there then you won't be able to complete this quest since you need to actually kill them DURING this quest for a chest to appear.

3) Missable relationships of Pen, Matilda and Yan, they are all gone at the same time about 70% into the game.
There are more characters who leave but other ones only leave for a certain period of time and eventually return.

4) Loads of missable 'masterpiece paintings' - they are all inside chests in combat locations you can only visit once.

5) Loads of missable 'books' - the missable ones are yet again in combat locations but usually not in chests making them even easier to miss.

6) Loads of 'event screenshots' are missable - they are sometimes in missable missions or can be missed by skipping cutscene.
For example You have to let Yan win on year 1 workshop competition as it's very likely you will otherwise not have him win anymore unless you stall story for a long time
I assume each person who CAN win in the workshop has own event scene for winning the yearly workshop. There are I think 3 such people, 4 if you include player character.

7) Loads of missable missions. This deserves own sub section.
1. Picking certain dialogue options often skips either a mission or an entire character quest chain outright. Usually something obvious like I don't want to help you but sometimes the dialogue choices you need are more obscure.

2. Some missions are limited to dating/not dating someone and sometimes not dating someone else too.
Not dating in most case means that the mission will allow you to automatically date the character without using the date proposal item.

3. Some missions are limited to when you have a certain amount of relationship but NOT dating.

4. Some missions are time limited - the least problematic most of the time, but do pay attention.

8) Mail replies - those don't play much role but you obviously can't see them all since you can only reply once. Not really much to be done about that however.
Overall ignorable and the most minor 'missable'.

9) Not exactly missable aside of characters who are gone but if you want to see all content you eventually have to date all dateable characters.

[Ragynn]

Yakmel Milk Cookies are missable. You can get them only in the mission "Bring a smile" where you build the stand for Mables desserts and cookies - and you only get them if you don't visit the opening, them Mable sends them per mail.