I’m about to have my brakes done. With the Prius, you don’t have to do this often, since the motor/generator does a lot of the stopping for you.
But I’m at 8 years and 140,000 on the one car, and I’ve worn them pretty good — to the point where I think they’ll recommend replacing the rotors (or maybe just turning them).
I don’t expect to drive the car past 250,000 miles, so I think this will be my only brake job. So it will cost me a bundle, and I’ll be done with it.
I did my own brakes in my older cars, and would buy rotors in a local junk yard where they would turn them for like $10.
I replace the rotors when I have brakes done now. They are not that expensive. I do my own brake jobs because it usually takes me about 15 minutes per wheel. I use dust free pads that don’t really cost all that much.
Oh, and I just did the first job on my Scion xB. It had 115k miles on it. When you commute 122 miles a day on open highway you get a lot of miles out of your brakes. :-)