If you find
Having a single harvest each year means there may be just one day when the whole year’s farm income arrives
OR
Paying bills that come in regularly can be difficult with a single paycheck
OR
It is difficult asking storekeepers and other suppliers to extend credit until the next harvest payment
OR
There is a lot of risk, stress, activity and demands around a single harvest each year, with everything building to a crescendo
Then,
On many farms there is one harvest with a heap of activity building to a crescendo.
And often building to high levels of stress and an increased financial risk because of a lack of income diversity and ecological Diversity.
A rolling harvest allows for more than one crop and thus more than one source of income, spreading the load, the income and the risk.
This gives more diversity of income over time and also spreads the climate risk by allowing for harvesting to happen at different times and in the process, ideally dodging some of the weather that might interfere with harvests.
However, having a range of crops or varieties (such as in an orchard where different peach varieties might reach harvest readiness one after another) allows for a spread of risk.
This is because if one variety, species or time in the market is hit by disease, market access issues or market flooding, there will hopefully be another that is not hit.
Sometimes you may be able to choose the different crop or variety to be one that is usually in the opposite stage of the cycle.
For example the old Up corn, down horn saying referred to corn (grain crops in the general sense, not just maize) prices rising at the same time as horn (animals and their meat products) went down.
This was because as grain prices rose, it became more expensive to feed animals with it and farmers would sell off their livestock. As grain prices fell, farmers would buy livestock to feed on the cheaper grain, forcing cattle prices up.
And of course, a lot of movements in markets are random or hard to predict for other reasons.
If you can make it so that you don’t have to harvest grain at the same time as the weather is perfect for making hay or at the time your sheep need to be mustered for flystrike control etc, then you can ease the stress on you and your family.