I have 17,800 miles on my 2012 and levels have remained unchanged. In other words, only trace amounts are consumed or lost during normal driving conditions. Toyota, along with other auto manufacturers write these statements in their manuals more or less as a disclaimer, not because it actually occurs. Although, before I started buying Toyota products, I needed to sneak in up to 1/2 a quart between oil changes for my JEEP G.C. and other Chrysler vehicles!