Replacing the hinge took no more than 10 minutes. The job requires only a Phillips #2 screwdriver and maybe a pair of pliers. If your hands are strong enough, you might be able to skip the pliers. Remove the oven door and storage drawer, unhook the spring, remove the hinge screws, and remove the hinge. Reverse the steps to install the new hinge.
I have replaced both hinges on my 22-year-old stove now, and in both cases it was the plastic roller that wore out. If your hinges start to work roughly, replace them promptly, because if the roller fails completely, the door may work very poorly.