When the wheels are rotated, i.e. every 7,500 miles.

Hi,

I'm sure there's a suggestion in the owners' manual, and it's probably
far less frequently than many of us check. So much depends on the use:
for example, I bought a used vehicle w/ 63k miles that needed brakes all
around--I'd expect pads in the front, but the rear shoes were just a
hair above paper thin, too. I doubt it had spent 5k of those miles on
open highway. But I also sold a vehicle I'd bought new and used on a
"straight shot" commute, 65 mi/each way, and when it went to its "new
home" at 189k miles, it still had the original rear shoes, in good
shape, and was only on its second set of front pads.

I still spend most of my driving time as "highway" time, so I usually
look carefully at the front pads every second tire rotation (about
12-13k miles.) Same interval if the vehicle's got rear pads. If it's got
drums and shoes, I'll usually look at them about every fourth tire
rotation.

Rick