Blocked DPFs are primarily caused by short journeys at low speeds. This is why manufacturers often recommend petrol cars for city driving. Poor servicing can also cause premature DPF failure. Regular maintenance is crucial, as a well-maintained DPF should last at least 100,000 kilometers. Using the correct oil is also important, as some oils contain additives that can block filters. Performance modifications, low-quality fuel, and frequently running the car on low fuel levels can also damage the DPF.