The logistics and expense of obtaining oil samples from wind farms are among the conditions that make it challenging to establish a valuable condition monitoring program. Optimizing the oil condition monitoring program for a wind turbine is a critical step towards achieving forecasted ROI for the wind farm. To advance the current oil condition monitoring practices for most wind turbines, 150 identical wind turbine systems in the field for up to four years were studied. Several oil analysis tests were performed to understand the depletion of additives and changes in fluid chemistry. Basic statistical analysis was obtained on the data set to identify correlations in the data. The result of the analysis was a better understanding of the wind turbine oil's formulation and the relationship to fluid degradation and gearbox condition. The statistical methodology that we performed can be applied to other wind turbine farms to improve the knowledge derived from their oil analysis tests, both for gear as well hydraulic oils. In addition, other innovative tests were suggested which may augment a current oil analysis test slate to improve the value of their program.