In my legal opinion there are essentially 3 circumstances that trigger the need for a Will. 

1. When you own a home. In Utah, if you have more than $100,000 or any real estate, your estate will have to be probated upon your death. A Will won’t avoid probate, but it does make it simpler and less expensive. 
2. When you have kids. As discussed in greater detail here, there is no inherent priority as to who serves as guardian of your children in the event of your death. The court is counting on you to make a designation and you do that in a Will. 
3. If you have a specific request as to where you want your money to go. In the absence of a Will, the state will employ what is called the law of “intestacy” to determine who should inherit your estate. Generally, this is going to flow as follows: 

If you have a spouse and all children are common between you, then your estate goes to your spouse. If you don’t have a spouse, but you have children, then it all goes to the children. If you have a spouse and children from a prior relationship, some money to both of them. If no spouse and no children, then to your parents. If no parents are living, then to siblings, and down to nieces and nephews, etc. 

But if you want money to go to a friend or a charity or in varied amounts to any of the above listed folks, then you need a Will. 

As an honorable mention, a Will can be helpful in the grieving process. A Will provides family with a way to know and honor your wishes. This can be comforting work for those left behind.

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