New alternators come with a warranty from the manufacturer and are generally considered more reliable and long-lasting than remanufactured units. They also tend to have better performance and efficiency, which can improve the overall performance of your vehicle.

Factors such as heat, vibration, and electrical spikes can eventually cause the alternator to fail. According to Repair Smith, your car's alternator may fail because of: Age and use-related wear. Engine oil of power steering fluid leaking onto the alternator.

The lifespan of a rebuilt alternator can vary widely depending on the quality of the remanufacturing process. A well-done refurbishment can result in an alternator that performs similarly to a new one, often lasting between 60,000 and 100,000 miles.