[header] How to flush power steering fluid [title] Check your owner's manual for the recommended power steering flush schedule. [step] Your power steering system is actually remarkable at staying clean. That said, over time natural wear and tear will cause bits of rubber, plastic, and dirt to enter the fluid, and this can cause problems to the entire system if the fluid is not flushed. 
Each car has it's own suggested interval after which you should change the fluid, so look up your model's time frame. [substeps] For high-end cars, you should consider replacing the fluid every 35-40 thousand miles.