Agree with both PPs. We filed separately once, early in our marriage, and I can't remember the reason. I think maybe he was a law student at the time and I was working and for whatever reason it worked out to our benefit to do so that one year. We did not itemize back then. I think that once you have significant deductions, and kids, it is almost always better to file jointly. We use TaxAct (online program that is much less expensive than Turbo Tax) and it will also look at both scenarios for you.