UK Car Repair: 04 2.2 Peugeot 607, peugeot 607, brake pads

Question
Roughly,how often should i be replacing the brake pads on the vehicle?

Answer
It all depends, my procedure is to check them every few months, usually at oil changes.  If they are close to 3/16th"  I change them.  It is better to change them sooner than later.  Brake pads harden with use and become as hard or harder, than the discs, so the disc begins to wear!