This is a perennial tax question. Usually filing jointly saves a couple taxes. And joint filing is required in order to use certain tax breaks. However, there are instances where filing separately makes sense. Strategy: Figure the taxes both ways (joint/separate) and choose the option that saves you and your spouse the most money. But money aside, if you are concerned about the tax liability of your spouse, separate filing avoids joint and several liability for the taxes on a joint return.
Test for determining deductibility of IRA deductions. Active participants in employer retirement plans are subject to IRA deduction phase-out rules if adjusted gross income exceeds certain threshold.