Originally Posted by chriszeh
i usually use a flashlight so i can get a better view if looking thru the wheel for quick check. the pads have a backing plate that is about 4mm thick on OEM if i remember and i shoot for having about half that amount of pad left or so(2-3mm) being all the way worn. this is also about the point where you will start to wear thru the sensor. if you change pads at this point before the sensor is damaged then a new one isnt needed. also the last little bit of pad seems to get used really fast particularly with track use.
Thanks man! I will get them replaced anyways for less brake dust. I have parked the car for now and will wait for pads and fluid. Need to pick up the sensors today for back up in case I do need them.