I need to replace left rear brake caliper. Should I replace right side too?

Hello, There is an excellent write-up on the estimate page for a rear caliper replacement. I encourage you to read up on the process by clicking the link below, and entering 'rear caliper' along with your vehicle info. I do not like changing one caliper without the other, however, if the caliper is the same exact type, it really should be ok, with a few caveats. Check out the estimate page, and see what questions come to mind. Let me know, and I'll help you out. https://repairpal.com/estimator/mazda/protege5