It really depends on your local environment, particularly the climate and weather it is regularly exposed to. The angle of your solar panels also plays a factor in how dirty they get over time. In most cases, you will want to clean your solar panels at least every 6 to 12 months. However, if your home or business is in an area constantly exposed to leaves, branches, birds, rainstorms, and airborne debris, then you may want to request cleanings every 2 to 4 months, just to be safe.