Many people believe that shell clothing should not be washed, but in order to maintain the functionality and properties of the shell jacket or shell trousers, regular maintenance is necessary. If dirt and grime are allowed to stick to the outer fabric of a shell garment over time, the garment's function will be impaired. When it is washed and re-impregnated, the jacket's waterproofness and breathability are maintained.
So although we recommend not washing your hiking clothes too much, it is important to regularly maintain your shell clothes.