Since most of you here are experts and I am ridiculously new to the DIY team, I'm hoping you can save me some research time. My brake lining light came on today so along with checking if the sensor is screwed up, I will check out the pads. I have not had any indication that they are wearing (no noise, car stops better than any car I've ever driven), but in checking them, what tool is best to measure the remaining life of the pad (a ruler?, I'm sure it's a bit more complex).

And with that measurement, how do i determine whether or not to replace? Unless of course it is so obvious when i look at them.

Mahalo