An old farmer I know let me in on his trick: don't work so hard. He said young and inexperienced folks would work way too hard, ie put in too much effort, and get exhausted quickly. Instead lower the effort so it's sustainable. Move slower, don't lift near your max and so on.
The advent of factories with limitless and constant demand for labor is a new development of the industrial revolution.
That doesn't mean that there isn't any downtime though. Most activity would be confined to daylight hours if nothing else. You'd probably do less on rainy days, and avoid hard work during the peak heat hours in the summer.
Not sure what anyone else did.
And in Catholic cultures (historically):
* https://en.wikipedia.org/wiki/Feast_day
The English word "holiday" comes from "holy day" after all.