I change the oil on my cars every 3000 miles....I know it's stupid but they do re-cycle motor oil so I don't feel guilty. And I have never had an engine breakdown due to oil related issues. I personally only use (and have for the past years) Castrol GTX, yet, interestly, FRAM filters work great! I use 10-40 in the winter and 20-50 in the summer. And heck, it only costs like $40 anyway right? Best of luck