Several factors can contribute to the deterioration of an exhaust system over time. One common issue is the buildup of condensation on the exhaust pipe or muffler, leading to the formation of rust. This occurs when the exhaust system heats up during operation and then cools down, creating an environment conducive to moisture accumulation. Over time, this moisture can lead to rust formation and compromise the integrity of the exhaust system. Regular inspection and maintenance can help prevent such damage.