You do one at a time. Dont need to have the car on blocks with all 4 wheels removed. But anyhoo. Your call. Just providing an option. I painted the calipers on my sons Tiburon 3 years ago when he first went off to college. Still look good to this day. Sure, they get dirty, but just take a brush and soapy water, good as new. No flaking or peeling. I used caliper paint you can buy at any auto parts store. I guess this is more of a project for do-it-yourselfers like myself. You want to pay someone to do it for you, go ahead. I'm not saying you can't or shouldn't. Total investment was just under $17 for the paint and probably 3 hours of my time.