My oven has both farrenheit and centigrade on it, and most recipe books are written or published in the States, so they usually have only the first. I only think in metric for things where I mostly use metric. Like, I think in litres of milk, not gallons, because the milk is produced, packaged and sold in Canada so it's measured in litres. I think in metres when I'm buying fabric, but not when I'm quilting, because the quilting patterns are written in inches. And so on, and so forth. It's very confusing.