Really? Neato, I've never seen that before. I guess my point is that barring any contamination or other internal weirdness, modern synthetic oils will last a long time, and the filter is the cheapest insurance to keep them that way. A filter for my Civic here is $4 or so. Synthetic is usually about $6 per liter at least, and my Civic holds 4.4 liters. So a filter swap at 3000 miles is cheap insurance, and saves wasting 4.4 liters of synthetic that still had a lot of life left in it.
