It depends on the type of pad and the manufacturer's recommendations. Generally, pads should be replaced every 3 to 5 years.Pads need to be replaced more often if they are not cleaned regularly. Dirty pads will develop a film that blocks the air flow and reduces the effectiveness of the cooler.

The pads in a swamp cooler should be replaced every 2-3 years, depending on the climate and the type of pad used. If the climate is very dry, then the pads will need to be replaced more often, since they will absorb more water. And if the climate is humid, then the pads will not need to be replaced as often, because they will not absorb as much water. The type of pad also makes a difference. Some pads are made from materials that last longer than others. So it's important to know what type of pad is being used in order to determine how often it needs to be replaced.