You don't have to unless there all bad but recommended if you do need to replace 1 front do both and vise versa
The brake rotors only need to be changed if they are worn beyond allowable specifications and should be changed in pairs. They do not need to be changed with the pads unless they are damaged as above or warped.
Need new rotors...pads in my case, same thing happened to me...
In general, normal wear can cause the rotors to become groved. The pads wear "into" the rotor during regular use. At some point, the rotors may need to be turned or replaced, and the pads may need to be replaced. Both the turning/replacing of the rotors and the replacment of the brake pads is done at the same time. Few if any professionals will attempt to "short cut" a brake job by just doing one thing.
I would always suggest replacing brake pads and rotors in pairs. However, if the pads still have a lot of life in them, at the very least take some sand paper and scuff the surface of the pads up. Over time, heat and other contaminates can cause pads and rotors to "glaze", or obtain a shiny appearance. If you don't remove the glaze off the pads, it will just transfer over to your new rotors, and may degrade braking performance.
If they are warped, they need to be turned, if they are groved, they need to be turned. If they are glazed, they need to be turned. In general, if you are working on the brakes, they need to be turned.If they are too thin (not wide enough across) to be turned, they need to be replaced. Many newer rotors are not thick enough to be turned, so you just replace them every time you replace the brakes. Most auto parts retailers will measure the thickness of the rotors for you and tell you if they can be turned.
This is often caused by installing new pads on worn or slightly worn rotors. Buying new rotors or turning the same rotors would make a smooth surface for the new pads to rub against. Any surface that is less than smooth will cause some grinding for a few days or maybe longer. It also shortens the life of your new pads.
If you brakes are still squeaking after you change your brake pads in any car, you have a warped rotor. The squeaking is caused by the rotor vibrating when pressure is applied by the pads. The best way to permanently fix the problem is to replace your pads and your rotors at the same time. This can also cause accelerated wear on the new pads if you do not replace the rotors at the same time, or at least have them turned.
YES, the pads should have been replaced at the same time you replaced the rotors.
It'll run you around $500-$800. The brake rotors have to be replaced at the same time as the pads because the original rotors were extremely thin.
Check with local parts store to see if they are the same part
Rotors are warped. Have them trued or replaced as necessary. Also replace the brake pads at the same time.
Warped brake rotors, have them resurfaced if thick enough and have the pads replaced at the same time. If the rotors are not thick enough they will have to be replaced too. Could be the ABS also.