Did your child graduate from college or graduate school this spring? If that's the case, this may be the last year you will be able to claim a dependency exemption for that son or daughter. But even then, you need to be careful to observe all of the tax rules covering such exemptions.

For starters, your dependency exemption for each qualifying child in 2017 is $4,050, the same as the personal exemption you and your spouse may claim. But you may lose some of the tax benefit of these exemptions under the personal exemption phase-out (PEP) rule. It kicks in at $261,500 of modified adjusted gross income (MAGI) for single filers and $313,800 of MAGI for joint filers.

To qualify for dependency exemptions, you must meet a two-part test. First, you have to provide more than half of your child's annual support for the year. Second, your dependent can't have earned more than the personal exemption amount in gross taxable income for the year. It's the second part of the test that often jeopardizes an exemption.