Your car is in the shop and the auto service manager says you need replacement parts that you can't afford. He gives you the option to have used parts installed, but is buying used parts a good idea? Used auto parts can work quite well and save you a lot of money in some situations. Here are some things to help you make an informed decision, and to make sure your used auto parts cause you as little grief as possible:

1. Talk to the auto service manager or technician and ask questions about the parts your car needs. Used maintenance parts such as brake pads, spark plugs and wires, or filters should never be purchased used, but used body panels such as fenders and doors, or window glass or trim pieces are almost always a safe, inexpensive alternative. Parts that sustain general wear like brake rotors, starters, alternators, engines, and transmissions should generally be purchased new, but there are exceptions to every rule. Don't hesitate to ask the auto service manager or technician for advice.

2. Take into consideration the condition, age, and mileage of the vehicle that the used part is being salvaged from. If the salvage car is the same age or OLDER than yours, the used part might not be a good bet, but if the salvage car is at least a year NEWER with fewer miles, you know the salvaged part is at least that much newer and a better bet for replacement parts. This information should be available from the used parts center, but if it isn't, don't buy the part from them.

3. Make sure the used parts come with AT LEAST a 30-day warranty in writing. That will give you enough time to resume your normal driving routine and decide if the used replacement part is going to be dependable.

4. Understand the auto shop's guarantee. Although the used parts may come with a warranty, many auto repair shops may not guarantee the labor cost to install it. Be sure you understand the auto shop's policy BEFORE they begin the repair.

5. Ask about aftermarket parts. If your car is more than five years old, secondary auto parts companies may make an aftermarket replacement part for it. Prices on these parts are often comparable to used parts prices, and the aftermarket parts are brand new with a better warranty.