[kevinande]

Personally I would change it about every four months considering where you live? Do you start and run the car every now and then or does it just sit? The other thing you could do is just change the filter every other change. In other words lets you change the oil in January, in May just change the filter and top off the oil. In September do a full change and so fourth and so on. The oil does not have a shelf life per say, but it does trap lots of impurities and condensation, that's why you want to make sure you have a good clean filter on there at all times. I had a T-bird that I ran 100% synthetic Mobil 1. I changed the filter every three months and a full change every year. That car had 176k on it when I sold it.