Regular window maintenance is important. If a window is not cleaned regularly it can stain and damage a window that will not be removable. ever noticed those water spots on your windows on a sunny day? this can be a result of being hosed down with tap water over an extended period of time! the Chloride in the water stains 
the glass…this is the reason our pure water / d-ionised system works so efficiently it takes out those impurities in the water giving a spot free shine every time!
Increased build up of dirt on widow frames is also a major factor in causing dirty run off every time it rains, you also have the intense summer sun “baking” the dirt on layer upon layer. In the window cleaning industry we recommend what we call “preventative maintenance” in other words, cleaning your windows often enough so that they don’t get back to the stage where you cant see out of them. Its a cost effective way of keeping your windows clean year round.