Every car is different and may require specific air pressure for your tires.
This can be found on the frame of your driver’s door. This plaque will also tell you the recommended tires you should keep on your car per the manufacturer.
This usually applies to your everyday driver that probably doesn’t have custom tires or rims that would null the recommended pressure for the car.
Edit: WHY you should know! (I forgot to add thank u @_MoveSwiftly!) So keeping your tires inflated is important because a) it keeps you safe. Properly inflated tires will have better stopping power B) wear and tear on a tire is lessened and wear and tear on other aspects of your vehicle that require good balance like shocks and brakes. c) in most cases having your tires inflated to the proper psi/bar will help you hit the MPGs, horsepower and acceleration advertised for your car.
I was driving the other week and my low tire pressure light went on. I opened the error page in the infotainment screen and sure enough it said “low tire pressure”.
I went to measure it and it was actually high tire pressure due to the hot weather. I let out some pressure and it went away.
So YSK that apparently cars will falsely report high tire pressure as “low” tire pressure and to always measure it before going to fill up.
Sounds like a faulty sensor