Q: severe driving condition

The vehicle manufacturer publishes a severe service schedule for your car. If I knew your year, make, model, and engine size I could give you a precise answer based on manufacturer data. The Owner’s Manual will certainly have the schedule. Manufacturers of synthetic oil publish "suggested" maximum intervals but these are typically based on average conditions and do not override the specific instructions for oil change intervals that are published in the vehicle owner’s manual. Broadly, though, for severe service if you are using a synthetic that is advertised for a 10,000 to 15,000 service interval, you can easily use that oil for up to 7,500 miles for most severe service conditions. If you desire that this maintenance be performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine oil/filter change and the responding mechanic will get that taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.