• Your assets are not titled properly to fund trusts. A common estate planning strategy used to preserve your estate tax exclusion is to set up a credit shelter or bypass trust. Assets up to the estate tax exclusion amount ($2,000,000 in 2008, scheduled to increase to $3,500,000 in 2009) are placed in trust. Your spouse can then use the income and even some of the principal, with the remaining assets distributed to your heirs after your spouse's death. To fund the trust, however, you need sufficient assets titled only in your name. Assets jointly owned with your spouse will typically pass directly to your spouse and cannot be placed in the trust. However, you may want to split assets so each of you individually owns assets designated to go into the trust. Residents of community property states should review their state laws carefully, since they typically have more flexibility when using assets to fund trusts.

• Beneficiary designations contradict your estate planning documents. Assets like life insurance, annuities, 401(k) plans, and individual retirement accounts pass directly to named beneficiaries. Provisions in your will and other estate planning documents cannot change those designations. Thus, review all your beneficiaries, ensuring those designations are compatible with your estate plan. Also review contingent beneficiaries, in case a beneficiary dies before you. After significant changes in your life, such as a divorce, remarriage, spouse's death, or child's or grandchild's birth, review your designations to determine if changes are warranted.

• Owning assets jointly with just one child. Often, a widow or widower will add one child to bank accounts, brokerage accounts, deeds, and titles, so that child can help manage the assets if he/she becomes incapacitated. The widow or widower expects the child to share the assets with his/her siblings. However, the asset is considered a gift to the one child. For that child to split the asset with his/her siblings, he/she will have to make gifts to those siblings, possibly raising gift tax implications. Instead, consider using a power of attorney, so the one child can help with your financial affairs. Or, make a provision in your estate planning documents that adjusts distributions for any assets that pass to one heir through joint ownership.