[paradon]

Generally the front pads wear faster than the rear in my experience as they bear the brunt of the braking force.

The pads are really easy to inspect and replace so I would be inclined to take the wear down until the notch in the middle of the pads flush which would be about 25% remaining.

You can get aftermarket EBC pads for about $100 a set so no real need to try and run them right down.