I've been reading that most people change front brake pads once every 4 years or so, rear ones even more rarely. Last time I needed to change rear pads, I put ECS red stuff on them (the front ones were generic ones I replaced a year before - didn't know I could customize them yet). Now, a year after I changed the rear pads, I started hearing grinding noise when I brake again. I checked my pads, the front ones seem unworn, the rear ones are around 4mm. I'm guessing they're wearing faster because they're better at braking so most of the force is on them? However, getting worn in a year still sounds a bit too soon to me.

 

Most 'upgraded' pads that have better braking power do so at the expense wear... the longest lasting pads are still the Semi-Metallic ones...