A friend of mine in high school (2012) was required to add to the notebook his parents kept in the car whenever he got gas. I wonder if his parents still do that kind of record keeping now that the car tells you its MPG, gas price historical data is easily accessible, and card purchases are tagged as "Gas" automatically in the banks that I use.

I do actually audit each transaction in my card statements each month to look briefly at the categories of spending I use most. Gas is a category, but that number doesn't really change my behavior. It's just a data point.

I’ve been keeping a spreadsheet of all my fillups. Mostly because I was curious about my monthly spend on gas with it having gone up so much. But it’s been interesting to see the mpg over time.