[Marty in NY]

Originally Posted by kevink1

My iDrive has been telling me I have between 3100 and 3900 miles to go on my brakes about 2 1/2 years now. Goes up on long enough road trips, down during city driving. I had them last checked last year when I got new tires, and I figured I had at least 20-30,000 miles remaining.

iDrive brake pad wear indicator is only a suggestion, think of it as a reminder but that's it, just a reminder. It has no way of measuring the pad or rotor thickness. The only way to do it is to look at each pad and rotor and if necessary, measure the remaining thickness. If you don't manually look and measure and only go by iDrive, you will probably grind into your wear sensor and possibly your rotors. The wear sensor is last ditch effort and if you avoid grinding into it, you don't have to replace it when you replace your pads/rotors.

[Merlin82]

iDrive and even the sensors arent as good as physically checking the pads yourself. I had a pad eat a rotor because the previous owner/shop that did the pads put them in backwards(there is an inside and outside pad). With a quick glance at the pads they looked ok but they were wearing funny. When I did the pads/rotors both iDrive and the sensors were saying I was good.