I remember a post a while back where Terry Dyson said that instead of flushes, he supported changing to synthetic with early filter changes until the engine was cleaned out... The general question to anyone is...how often should these filter changes be made. I changed to Amsoil in an engine that had 40,000 miles on conventional oil. I did flush it with the Amsoil flush, but am thinking about changing out the filter early, I have two Amsoil filters on the way, so I am not worried about wasting the existing filter. should I change at 1000miles? when the oil is black? 3000miles? thanks I was not sure if this should go in oil or filters, so if it should be moved, feel free.