Over time, various factors can cause roof granules to become dislodged or deteriorate. Severe weather, such as heavy rain, hail, or wind, can strip away granules, leading to granule loss and exposing the underlying asphalt layer to potential damage. Sun exposure can also degrade granules, making them less effective at protecting the roof. The age of the roof itself is another factor, as older shingles may experience granule loss simply due to time and wear.