It depends on the quality of the fireplace. A high-quality prefab fireplace can last for upwards of 40 years, while a lower-quality one might only last 10-15 years. The most important factor in determining how long a prefab fireplace lasts is the quality of the material used in constructing it - if it's made from cheap materials, it's likely to wear out sooner. So, if you're looking for a long-lasting fireplace, be sure to choose a high-quality model.

A prefab fireplace typically lasts 10-15 years. However, with proper maintenance and upkeep, a prefab fireplace can last up to 20 years.