Spring is an awesome time to render care toward your vehicle. As it is, your vehicle most likely incurred some winter weathering. And any issues be they noticeable or hidden may become worse if not remedied soon and completely. With brake calipers and rotors, the signs might be obvious while others not so.
Brake System Health, Maintenance
Obviously, brake calipers and rotors work in concert. Serious wear could signal issues with tire alignment or just need of replacement parts.
It's easy to inspect the brake system of your vehicle. While bending or kneeled, look through the spokes and note if the rotor disc has been ground below the casing circumference. Such a condition will be noticeable when applying the brakes given grinding sounds or squeaking. Then, it's time for a servicing appointment posthaste.