Brakes feel fine stepping on them until your about to stop , then they grind and squeak Rotor look fine i dont see or feel and bas spots on them . Should i replace pads only or both pads and rotors?
The pads are most likely becoming embedded with sand particals. Mine started to do it after a few sloppy sandy mud rides. My pads only had about 20% remaining put new pads on and was good. Normal trucks and jeeps can get this same issue if driven in a lot of silty sandy mud
One thing we used to do, back in the biking years. If the pads got noisy, it was probably road sand/gravel/debris. So next stop for the night. Get a cold beer, a nice section of concrete sidewalk.
Park the bike by the sidewalk, take the pads off and sort of sand them on the sidewalk. Didn't take much to get all that s**t off the pads and having the pad surface flat and clean. Put the pads
back on. Get another beer and a steak. Lock up the bikes. Next morning all that noise and bit of lousy braking is gone. Do it whenever the pads get noisy until the pads are worn out.