To decide how often you should use fuel injector cleaner, you need to look after numerous factors. You need to determine how much you drive your car. How old your car is and what type of fuel it needs. If you have a gas vehicle, you need not clean it that often. But if your vehicle contains a diesel system, you need to clean it more regularly. Check the instructions of the injector cleaner you are using. You will find most of the information there. Generally, you should clean your car every 1,500 to 3,000 miles, depending on the type of fuel system you have.