If you are married, you must file a joint return in order to claim any of the following tax breaks:

• the dependent care credit
• the earned income credit
• the HOPE scholarship credit
• the lifetime learning credit
• the deduction for interest on education loans
• the adoption credit
• the exclusion for interest income on Series EE U.S. Savings Bonds used for higher education expenses
• the $4,000 deduction for IRA contributions for a nonworking or low-income spouse

In addition, married couples who lived together at any time during the year must file jointly in order to claim any of the following:

• the more lenient phaseout rules (i.e., phaseout between $156,000 and $166,000 in AGI) for the IRA deduction when an individual does not participate in an employer-sponsored plan, but their spouse is covered by an employer's pension plan
• the credit for the elderly or the disabled
• the $25,000 rental loss allowance under the passive loss rules

Beyond these listed items, you should be aware that if a couple files separately and one spouse itemizes his or her deductions the other spouse must follow suit - the standard deduction may not be used. Also, if either spouse is receiving Social Security benefits, the amount of benefits on which income tax must be paid is higher for spouses filing separately.