Brake pads are supposed to last between 25,000 miles to as much as 65,000 miles.
The actual miles that brake pads will last depends on your driving and how often you use the brakes to stop the vehicle.
The less often you use the brakes the longer your brake pads will last and the more you use the brakes the more your brake pads will wear out and faster.
If you do a lot of city driving and stop the vehicle a lot for traffic lights then your brake pads may only last 25,000 miles and sometimes less.
However if you do a lot of highway driving then your brake pads may last as long as 50,000 to 65,000 miles before needing replaced.
Your brake pads have a wear indicator on them that make noise by touching the surface of the brake rotor when you're stopping the vehicle.
When you hear that screeching or scraping noise then your brake pads are likely worn down and need replaced.
If it's been more than 30,000 miles and you haven't replaced your brake pads then it's likely about time to replace them with new ones.
Your brake shoes should last the same amount of time and it's recommend that if you have brake shoes as well as brake pads that they all be replaced at the same time.