Is there a certain timeframe in the game when you need to send your letters to your villagers?

[Tyrael]

For them to get them the next day? I usually send them letters daily with gifts, but sometimes they don't arrive on the next day but instead a day later.
Is this intentional or RNG as well on who responds and when?

 

[Altarium]

I wondered this too, it's so inconsistent! I tend to write them always at the same hour (10PM) and sometimes I get replies the next day and sometimes I get them 2 days later. I have no idea at this point lol.

 

[Tyrael]

I know right, it's really inconsistent. I wish it was explained somewhere but it is probably rng again.

 

[Ananas Dragon]

I know right, it's really inconsistent. I wish it was explained somewhere but it is probably rng again.

and we all know rng is a piece of foxtrot