While the reliability of a used car part varies depending on the part and how much wear it has, Toyota is one of the most reliable vehicle manufacturers, as of 2015, which means its parts also tend to be reliable. Used Toyota parts typically provide good value, as they match the car like a new Toyota part but don't cost as much.
Used and new Toyota parts each provide benefits. Since new parts have never been used, they haven't sustained any wear and tear that could reduce their lifespan. These parts also have a warranty through Toyota. Used Toyota parts may also have a warranty, but the warranty for a new part is typically longer.
Used parts can work just as well as new parts for a lower cost. To ensure that the used part is in good condition, the buyer should research that part as much as possible.
Aftermarket parts are another replacement part option that often provides savings over new Toyota parts. The quality of these types of parts varies considerably. Some aftermarket parts are better than manufacturer parts, as the aftermarket company figured out how to work around previous flaws while reverse-engineering the part. However, others are much worse due to lower-quality materials.