The disclaimer is easily one of the most useful devices in the estate planner's kit. Using disclaimers artfully, the planner can sculpt a dispositive pattern after death has occurred and all variables are known including asset values, asset ownership patterns, needs of the family (at least as of the time of the decedent's death) and state of the tax system. All of these factors may be shrouded in uncertainty at the time the estate is planned before death and the instruments are drafted. Disclaimers permit a late opportunity to carry out the testator's wishes and to do so in a rational manner. The problems with disclaimers tend to revolve around an unwillingness to disclaim by those receiving interests in property, even though disclaimer would clearly be in the overall family interest (but not necessarily in the disclaimant's interest), some uncertainty over who can disclaim and the technical requirements for a disclaimer to be effective.