Draperies, valances, shades and blinds are all very beautiful on windows but do you know they collect lots of dust? My recommendations are regular vacuuming at least once per month. Have them professionally clean once per year. Yes, they never look dusty but when touched dust starts flying around in the room. A closer look also reveal dust sitting on the fabrics. Dusty drapes or any other window treatment is a no no for allergy sufferers.