I’m going to continue musing on world-building. A central factor of a person’s or a society’s existence is timekeeping: calendars, the breakdown of the year into seasons, months, weeks, etc.
Tolkien dealt with this by using the conceit that he was publishing a translation of an older work. That, yes, he was using Sundays and August, etc., but that the original work used entirely different terms. He was merely employing contemporary calendar usage for familiarity.
This works well enough if the world in question is intended to be ours in an earlier epoch. But does it create a dissonance when the world is something else entirely, but the characters are referring to Tuesday, July 2nd instead of, say, the fourth day of the Blood Moon?
Of course thinking about that can raise other issues, depending on how deep one wishes to drill. Time depends upon planetary rotation and the circuit about the sun. So, if it isn’t Earth, a twenty-four hour day and a 365-day year is unlikely. On the other hand, is that level of detail and realism necessary? Does it place unnecessary burdens on the reader, requiring him to learn and absorb an unfamiliar calendar in order to appreciate the story? And if having a thirty-hour day and a 220-day year broken into ten 22-month periods contributes nothing to the story, is it worth doing? Is there a level of world-building that harms storytelling?
I think an argument can be made for simplicity: keeping a familiar diurnal and annual cycle. But using our standard terminology is probably a bit much. Meaning creating new names for the days of the week and the months of the year might be the proper balance between world-building and smooth storytelling.