When servicing a car yourself, such a check is most important. It should be carried out regularly. The brake pads on the front wheels wear out fairly quickly, especially on vehicles with automatic transmission.
The brake pad wear warning light in the instrument cluster lights up when braking if the thickness of the pad lining on the piston side of the front wheel cylinder becomes less than 3.5 mm. Usually, with this wear, all four front pads should be replaced.
When installing new front pads, always check the condition of the rear pads.
You need to remove the wheel to check. The maximum allowable wear for the lining of the front pads is 3.5 mm, the rear pads are 2 mm.