The car has done 105k km in a little over two years, and the sensor light has just come on. I bought new pads for the fronts - they have about 4 or 5mm left from my quick inspection with the wheels still on an the rears look fine. I'm planning on doing the pads this week, and I have new rotors as well. I'll measure the existing rotors and check what they have left.

I know they start at 25mm, so i'll check the minimum size and if they have more than 55% left and they look ok, i'll probably keep them on.