While the Federal lifetime gift limit is very generous and portable—for example, if your spouse dies before you, his or her $5.34 million exclusion is added onto yours, for a total of $10.68 million—many states are not that generous.
If you live in a state with a death tax, like Maryland (currently $1 million but scheduled to increase and match the federal exemption by 2019) or New Jersey (currently $675,000), you may want to consider setting up trusts for assets in excess of your state estate-tax gifting limit.
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There's a debate about whether these trusts are necessary, given the high federal limit, but if you live in the District of Columbia, for instance, where the state estate tax could be as high as 16 percent, you may want to consult an estate-planning attorney about your specific situation.
Changing circumstances, whether personal or driven by economic conditions or estate-planning laws, are your cue to revisit your estate plan. Don't ignore them, because the potential mistakes or advantages can be significant.
—By Barry Glassman, special to CNBC.com. Glassman is founder and president of Glassman Wealth Services.