[Black Leviathan]

In the absence of a usable calendar/clock system from the world they originated from a society would count the length of days by their average cycle, break them down into the Mid-day and Mid-night and then further down as technology allows. Some clever inhabitant would develop a water clock or hour glass to help order the day. If their planet has extra wobble they may later develop a "daylight Savings Time".
Whoever is growing food would have to find some pattern in the chaos of the seasonal cycle to plan planting and harvest. If there are multiple bodies influencing seasonal weather they would establish a method for discerning which type of growing season they were going to have and build an almanac to help farmers. So if the 70 day growing cycle was the "Siepus" Summer, the 40 day growing cycle is the "Horcus"Summer, then the 91 day growing cycle is the "Great Siepus" .They cant grow anything in the 19 or 21day cycle so they just call them "Nomus". Then they follow the different cycles until they can identify a pattern they can use to predict the next cycle rather than relying on unreliable predictive signs. The more eccentric these cycles become the more the society would be obsessed with calendars to understand them.