Keep track of the fuel efficiency of your car.Entering the odometer reading and the fuel bought every time you refill your tank you will be aware if your car is working as it should.
Good idea to say the least. Many loyal BMW Baby boomers keep a lil note book and write down every fil, every oil change, every mile, and the price of gas and store it in their glove compartments. My Dad has been doing this since his early 20's. I'll show him this but it's a long time tradition and it's done as they would say by hand rather than a computer which is a 2nd step to slowing down the brain from it's desired harmony with technology! Ya gotta love our intellectual elders who believe in "keeping your brain smart and sharp as you also, keep up with technology of today!"