How often should I do a transmission flush/filter change on my vehicle?

I have a 2003 Chevy Cavalier, 4 cylinder automatic.. How often should I do a transmission flush or change my transmission filter?|||change the filter and fluid either every 15'000 miles, every 30'000 or never. a flush just changes the fluid but does nothing for the filter, the danger of either is as the transmission wears the clutch material gets picked up by the fluid, if you replace the fluid you loose the material and the transmission may slip, if the fluid is really dark do not change it, if it is just starting to dicolor, change the filter and do a flush.|||Change the fluid and filter every 15,000 miles or once a year. If the transmission is healthy, I would only recommend flushing on older vehicles with high-mileage. Fresh transmission fluid is a dark pink colour. It shouldn't be dark brown or black, or smell burnt.|||the owners manual in your glovebox should say.|||75,000 to a 100,000 miles|||it should tell you in a manual it depends on the make and model usually