Unlike other Hydroponic systems the answer is more flexible. There are several variables that determine the answer.

1. Type of Coco coir. For example in a given green House, the 16 mm material will require less cycles than Crush.
2.  Climate.  A hot climate will require more frequent irrigating cycles.
3. Stage of growth. As the plant grow, its need for water supply increases. In order to satisfy its ever growing  demand  for water, more water should be applied (In some cases this growing demand can be satisfied by increasing  the duration of each cycle without increasing the number of cycles per day).
4. System limitations. Some big farms have a lot of irrigating valves. Sometimes increasing the number of cycles in one valve restricts the ability to irrigate with another valve.

The decision about the number of cycles per one day should take into account all of the  parameters mentioned above.

1. Pelemix will never use pre-mature raw material.
2. Pelemix has double sieving devices which enable the company to remove  fine dust and guarantee that air content is maintained around 20%. Most Coir-Coco-peat producers are not aware of the importance of double-sieving process.
3. Pelemix's growbags weigh more than it's competitors, and therefore the volume of the growbags is not reduced dramatically during the crop period.
4. Pelemix is using thicker plastic for its products and guarantees a longer useful life.
5. In order to help its customers, Pelemix provides periodical visits by an agronomist, to give the growers professional advice.

Pelemix does not use premature raw materials (except for  crush material). Therefore Pelemix Coir products will last much longer than any product produced of other companies. When using growbags, the limitation of use is determined by the quality of the plastic. Even when using growbags with plastic for 3 years, the plastic will start to disintegrate long before the Coir is unusable.

As for the Coco coir itself,  the material will start loosing its characteristics after about 3 years (except for crush material). The best way to determine if the Coco coir should be replaced is by testing its physical characteristics in a trustworthy laboratory.

Unlike soil, a soil-less substrate doesn't contain the nutrients that are essential for plant growth. Therefore, all nutrients should be supplied through irrigation. It is normally recommended to use at least two tanks for different fertilizers and another one for acid. Keep in mind that the Urea is very likely to wash out of a soil-less substrate before becoming available for the plant.