Somewhat like Sanny, my Prius has changed my driving habits, not specifically in pursuit of maxed MPG (although I sure enjoy getting better MPGs). I find I'm less rushed, more relaxed and now only glance occasionally at the MFD (reading "Consumption"). I have reduced my tire pressures to 38/36 psi. I have changed to Mobil-1 5W-30 (yesterday) and will watch the mpg readings. I used my independent (long time) mechanic, changed the filter, put in 3½ qts (took the other ½ qt home) and noted the dipstick was just below the "full" dimple.