Descaling your coffee brewer or espresso machine is one critical maintenance step to ensuring the longevity of your equipment.  Minerals in the water you brew coffee with will overtime create mineral deposits called scale on the interior of your equipments heating elements/boiler, which will negatively impact the heating elements/boilers performance and can clog water flow.  The type and quantity of minerals in your water will be the determiner on how often you should descale your brewing equipment.  The harder your water the more often you will need to descale your brewing equipment.  The following link provide instructions on how to use the product: https://www.durgol.com/global_en/products/durgol-swiss-espresso.