It is crucial for you and your spouse to have a good Will in place; especially if you have children under the age of 18. Why?
Because you must decide who will be the guardians of the kids if something happens to you both. Here is an example of what you need in the Will:
If my Spouse fails to survive me, or if he/she dies after my death without having appointed a testamentary guardian for any minor child of mine, I appoint ____________________ to be Guardian of the persons and estates of those of my Children who are under the age of legal majority at the time of my death, without requirement of bond or other security.
Otherwise, the Court will be deciding who gets to take care of your minor children.