Regularly cleaning and maintaining your siding will help keep the color from fading, also increase the lifespan. This allows the owner to see what damages that may accrued during the winter months. Consistent maintenance keeps mold, dirt and animals from making your house their home!!! L.O.L. Not cleaning on a regular bases allow harmful substances like Algae, Bacteria, Fungi and insects to live on and under your siding/wood.This will create a unhealthy environment for young children and older adults.