I do 7000 mile oil changes. I have no oil comsumption at all. No one drives any harder than I do. But, a little oil consumption isn't bad, especially if it is just "blow by" the crankcase ventilation mentioned above. If it is blowing blue smoke out the exhaust, you would see build up over time. What does the inside of your exhaust look like at the tips? Wet, black carbon, gray???