An irrevocable trust is just as its name implies, it cannot be revoked or changed once it is established. An irrevocable trust is used to lower estate taxes by gifting property to it. To save estate taxes, however, property must be "given away" to the trust. This means that once the property is given away, you cannot receive any benefits from it. Thus, one does not use an irrevocable trust as an estate planning vehicle unless you're willing to part with all control and benefits from the property to be placed in the irrevocable trust. One uses an irrevocable trust in place of an outright gift to a beneficiary because you want the money for the beneficiary in the hands of a trustee instead of the beneficiary (minor grandchild, adult child you cannot handle money, etc.).