I have a AirTag in my car so I can find it when I park in an unfamiliar city or an airport parking lot. I'm imagining a rechargeable version I could plug into the cigarette lighter and it would theoretically last as long as my car does.
When I get out of my car, my iPhone remembers that this was the last place it was connected to the car's Bluetooth. I don't have an special devices or tracker apps or anything else, just "Find My" automatically pinning my car's location on the map. That's such a neat and helpful feature!