Why does heating and cooling cause wear and tear on a machine?

Heating and cooling cause wear and tear on a machine primarily due to thermal expansion and contraction. As materials heat up, they expand, and when they cool, they contract, which can lead to stress and fatigue in components over time. This cyclical process can create microcracks, misalignments, and other forms of mechanical degradation. Additionally, temperature fluctuations can affect lubrication properties, further exacerbating wear.