Generally, you should clean your throttle body around 75,000 miles. If you are not experiencing any symptoms of a dirty throttle body, you can wait longer to perform the cleaning. However, as soon as you start experiencing symptoms, you should go ahead and perform the cleaning. The process is pretty quick, and a can of cleaner will only cost you about $10. This is a cheap maintenance item that you can perform yourself, and it can really make a difference in how well your engine runs.