Maybe I'm in denial, but I would much rather have a device and accompanying app to tell me about my car's health than my own. Good thing I have almost as many choices of what kind of WiFi car diagnostics tool to buy these days as I do wearable activity tracker.
This particular scan tool, like most, plugs into your car's On-board Diagnostics (OBD) port, and sends information about the vehicle to one of several available smartphone apps (your choice, this is just the hardware) as you drive. Get instant and continuous readings of actual miles per gallon, airflow, and tire pressure, plus notification of issues, and their corresponding trouble codes. So you can determine without dragging your car to the shop why, say, the check engine light came on. Again. (Just a loose gas cap. Again.)
Unlike other OBD tools, this model from iKKEGOL turns off automatically afer 30 minutes of non-use, so you don't have to plug / unplug it each time you get into and out of the car, and you don't have to worry that forgetting will drain your car's battery if it sits plugged in overnight.