I have a 2002 Nissan Frontier PU with only 70K miles on it. For the last three years or so I've only put 2500K or fewer miles on it per year. I see this continuing for the foreseeable future. I have been changing the oil every year and the filter (Fram Ultra) every other year. I've been using ST 5w30 for my fills. Would there be any downsides in doing the oil change every two years rather than every year with the same products. It just seems a waste of good oil but I'll continue the yearly changes if it's appropriate. I do take the truck out at least once or twice a month for a run up the freeway to get the oil nice and warm. The truck is garaged and here in Denver we have very little humidity/condensation to worry about. Thanks.