I am surprised that the following lube tip was excepted and rewarded; "I have set up a PM to change out synthetic oil in gear boxes every 24 months. Three months before the PM kicks out to change the oil, I have another PM kick out to sample the oil before I change it. If the sample comes back with no issues, postpone the oil change another six or twelve months, whichever is best for the gear box in use. (Ron Utt, PM Team, Weyerhaeuser)"

Going 21 months without sampling oil is not preventive or predictive maintenance. If the equipment is such that it can go two years or more without a change, then by sampling monthly or at least quarterly, why change the oil before sampling indicates the need to do so? That's a waste of money and resources. I have equipment that is running on synthetic oil that is 8 years old.

While 21 months without an oil sample may seem like a long time there are pieces of equipment that it just does not make economic sense to spend the time and maney sampling. If you can justify scheduled changeouts on some of your smaller less critical gearboxes, hydraulic systems or pumps then using oil analysis as a tool to optimize oil life makes perfect sense.