Most maintenance experts realize that the "average need" usually determines the oil–change intervals for both engines and transmissions. No two pieces of equipment have the same preventive maintenance needs. Each machine has different imperfections and operates under different conditions. Operators performing smaller or lighter jobs can cause different conditions on engine and transmission wear than those that occur during more extended use. When using oil analysis to determine maintenance intervals, little guesswork exists. Records show that some equipment can run safely two or three times longer than recommended intervals. The oil analysis may show that you are changing the oil more often than necessary-or not often enough. By eliminating too–frequent oil changes, you reduce the cost for oil and servicing, and also reduce the amount of used oil. Doing this can reduce waste oil dumping charges or the need for expensive oil and oil filter recyclers.