The decision to buy new or used parts depends on various factors. Here are some points to consider that may help you make an informed decision:

1. Cost: Used parts are generally cheaper than new parts, so if you're on a tight budget, buying used parts might be a good option.

2. Age and Condition: The age and condition of the part can also play a significant role. If the part is relatively new and in good condition, it might make sense to buy it used. However, if the part is old or worn out, buying a new one might be a better investment in the long run.

3. Warranty: Most new parts come with a warranty, which can provide you with peace of mind and protection against any defects or failures. However, used parts typically do not come with a warranty, so you will need to rely on the seller's reputation and the part's condition.

4. Availability: Sometimes, finding the exact part you need can be a challenge, especially if it's an older or rare part. In these cases, you may have no choice but to buy a used part.

5. Safety: Certain parts, such as brake components, steering components, and safety belts, are critical to your vehicle's safety. It's generally recommended to buy new parts for these components to ensure they are in good working condition and will function properly in an emergency.

Ultimately, the decision to buy new or used parts will depend on your specific needs and circumstances. It's a good idea to weigh the pros and cons carefully before making a purchase. If you're unsure, consider consulting with a mechanic or parts specialist for advice.