I have had my 03 Ram for a little more than a year (bought Oct 2002) It has 8100 miles, changed oil twice. I was going to wait for the next oil change to change out the fuel filter (going to be around 10,000 miles). The question is that I may not change oil for another 4 months, this will make the oil filter about 1. 5 years old. Is the oil filter need to be changed based on mileage only or does time play into the replacement?