At what age should my young adult children do their wills?

Depends. Wills provide a legal way to pass on personal assets according to the wishes and hopes of the maker of the will. A will is unnecessary until there are a moderate amount of assets to be passed on. This is especially important if there are children or a spouse. In this age group, the major cause of death is accidental as illness in this age group almost always allows time to make a will.