What factor does NOT influence the accuracy of oil samples?

The factor that does not influence the accuracy of oil samples is the time since the last oil change. While the time elapsed since the last oil change can provide context for the overall condition and potential contamination of the oil, it does not directly affect the sampling process itself. The accuracy of an oil sample is primarily determined by how the sample is taken, ensuring that it reflects the current state of the oil in the machine.

In contrast, the cleanliness of the sample container is critical because any contamination introduced at this stage can skew the results of the analysis. Machine operation prior to sampling helps ensure that the oil is well-mixed, providing a representative sample of the oil in use. Lastly, the location from which the sample is drawn within the sump can also significantly affect accuracy, as different areas may contain oil with varying levels of contaminants or wear particles. Thus, while the time since the last change may inform maintenance decisions, it does not impact the precision of the current sample being analyzed.