You and your spouse should discuss how you want assets to pass to the surviving spouse at the death of the first- to-die. This issue can arise in two very different contexts. First, if your estate plan creates a Credit Shelter Trust (sometimes called a Bypass Trust or a Family Trust), then you may want the surviving spouse to be a permissible beneficiary of that trust. However, the surviving spouse cannot have too much benefit/control, or else that would negate the estate tax planning for such a trust.
Second, assets other than those funding the family trust usually pass to the surviving spouse, either outright or in a marital trust. A marital trust can give added control, professional management of assets, and protection from creditors, while still preserving certain estate tax savings. If a marital trust is used, consider how you want distributions to be made for the benefit of the surviving spouse. Many trusts for the surviving spouse allow liberal distributions for such needs as medical support, living expenses, and general welfare. To qualify for the estate marital deduction, trusts for a surviving spouse generally must at least distribute the trust income to the surviving spouse at least annually.