By definition, a pour-over will is one in which you instruct your executor to pour over all of the probate assets you own at your death into one or more trusts that you established during your lifetime. In other words, your pour-over will designates only your trust(s) as your heir(s). You name your actual heirs in your various trusts. 

FindLaw explains that your pour-over will consequently serves as your estate plan’s catch-all document. 

Advantages 

The main purpose of your pour-over will is to make sure that your estate assets pass to whom and in the way you intend. When you establish your trusts, you place assets into them for the benefit of their designated beneficiaries. But what do you do about assets you acquire after establishing your trusts? Keep rewriting and updating them? Not if you execute a pour-over will. 

Your catch-all pour-over will ensures that when you die, your executor; i.e., your probate estate administrator, will immediately pour over any assets you still personally own at the time of your death into your designated trust(s). They thus go where you intended them to go, even if you forgot or neglected to place them in the trust(s) during your lifetime. 

In addition to the peace of mind that your pour-over will gives you, it also makes probating your estate quite easy and quick for your executor. This, in turn, makes your probate assets more immediately available to your ultimate heirs. How? Your estate administrator need only ask the probate court to grant permission for him or her to pour over your probate assets into your designated trusts as quickly as possible per the instructions in your Last Will and Testament. The trust assets then pass to your heirs without further delay or court oversight.