This is uncertain. You'd better not listen to the 4s shop. Their goal is to make money. Generally, if all synthetic engine oil is used, it can be replaced at least on 10000- 12000. If you often run the expressway, you can change it around 15000. Generally, the original engine oil has average performance. For home use, a noon of around 400 is generally enough for all of synthetic engine oil. For domestic use, at least 10000 to 15000 km should be replaced.