Brake rotors last between 100,000 miles to as much as 200,000 miles depending on how often you use the brakes.
It's recommended that you replace the brake rotors after 100,000 miles because by then the brake rotors can start wearing down and getting thinner.
After around 200,000 miles it's also recommended to replace the brake calipers as well or whenever you replace the brake rotors then replace the brake calipers because brake calipers can become stuck and cause damage to your new brake rotors.
Brake pads can be replaced without replacing the brake rotors as long as the brake rotors are in good condition and not cracked or warped or are rusting out really bad.
Brake Pads typically last between 15,000 to 30,000 miles depending on how often you use the brakes.
if you do a lot of stop and go city driving then you will need to replace your brake pads sooner at around 15,000 miles to 20,000 miles.
If you do a lot of highway driving and don't use your brakes much then you may get 30,000 to even 50,000 miles out of a set of brake pads.
The more you use the brakes the faster your brake pads will wear out.
As for brake rotors the brake rotors usually last around 150,000 to 200,000 miles before they need replaced.
So yes you can replace your brake pads without replacing your brake rotors if the brake rotors are in good condition.
I usually replace my brake rotors at around 100,000 miles just as preventative maintenance.
That means that I get around 4 sets of brake pads changed out before I need to replace the brake rotors and 100,000 miles is a lot of driving.
I order brake rotors, brake pads etc online and it's cheaper that way.
You can order brake rotors that come with brake pads online for most vehicles for around $100.00 with shipping.
For most vehicles replacing brake rotors is pretty easy but if you're not comfortable with it then hire a mechanic to do the job.
Paying a mechanic to replace the brake rotors and brake pads will cost more than doing it yourself but if you're unsure on how to replace them then a mechanic is recommended.