A mechanic, Juanjo Jiménez, reports a shift in vehicle maintenance habits is leading to increased engine damage. He observes that car owners are delaying oil changes beyond recommended intervals, despite advancements in engine technology. Jiménez explains that while modern engines *can* operate for longer periods between oil changes due to improved oil quality and engine design, owners are often exceeding even those extended intervals. This practice, he argues, ultimately harms the engine. He notes a historical standard of changing oil every 10,000 kilometers, but believes current practices are pushing those limits too far. Jiménez suggests he has developed a theory regarding optimal oil change frequency based on these observations.