The costs of fungicides, miticides, insecticides, foliar nutrients, wetting agents and plant growth regulators continue to increase. For a full spray program on apples, for example, the cost of spray materials alone could cost $800 to $1700 per acre per year. A poorly calibrated sprayer applying an average of 10% more material than intended, directly increases production costs by $80 to $170 per acre. Nozzles on sprayers wear out over time, and flow rates increase as nozzles wear, with worn nozzles eventually increasing flow rates by 10% or more. Financially sound management requires carefully calibrating orchard sprayers to optimize the benefits from applying spray materials.