I'm not understanding your question. You mean oil change? Or washing the engine? I'm assuming you mean changing the oil, since you're titling it synthetic oil users. I'd actually like to see a poll done for this question, just to see the margin of synthetic users and how long they go w/o changing the oil. Personally, I got 5k miles w/ Mobil 1 5w-30 w/ motorcraft oil filter.
