I have 230000Km on my 91 LS400 and 110,000 Km on my second set of pads, which I bought from Lexus Canada. The first set had more than 110,000Km on them when a caliper seized and caused a pad to wear out early. The fix for seized calipers is to remove the pistons and sand out the outer lip of the cylinder where the rusting and jamming occurs. Next I completely fill the rubber boot around the piston with brake silicone lubricant, thus reducing or eliminating the contact with salt water. So far I have gone 4 years with no sign of seizing.
Flush your brake system once each spring. Only takes an hour and a little brake fluid. Much better than badly seized calipers, or even worse a corroded ABS system.
The way I drive, not heavy on the brakes, slowing down early for lights that are going to be red anyway, I don't accumulate much brake wear. I also use my gears for long downhills, rather than the brakes. If you drive aggresively I'm sure the pads and disks won't last long.
A major cause of disk warping, and the resulting vibration, is excessive use of brakes on long steep downhills, rather than using a suitable lower gear. You have to get the engine above 1800 rpm where the fuel cuts off, and on a steep hill 3000 or 4000 rpm for max braking.
If you have hot brakes and drive thru a pool of water the sudden cooling will warp disks pretty quickly.
I have followed cars driving down from ski mountains and seen smoke and steam pouring out from the brakes. Relying entirely on the brakes on long slow steep downhills can leave the brakes glowing red.
Ernie in Vancouver BC Canada