When I said that not once have I seen it work I was not completely correct. I have one client that I file separate income tax returns on and it has nothing to do with income taxes but rather the amount of money  the wife would have to pay back on her college tuition.  Filing separately her and her  husband paid alot more in income taxes but it was a drop in the bucket to what the addional amount she would have had to pay torwards her  government college tuition had she and her husband filed joint returns.