There is no scheluded service interval for turbo chargers. It need to replaced when it goes bad (oil and coolant leak into intake system, excessive noise from bearing). It can happen with a car with 5k. More you abuse it, the sooner it goes.
ask your mechanic to look at them next tune up or oil change they will tell you. it all depends on how often you drive and how you drive...i like to show of in my car.