Every adult should undertake some level of planning. Just how much planning depends on the assets the person owns. Even a newly-minted 18-year-old should have documents appointing agents for medical and financial decisions if he or she becomes incapacitated, and should think about his or her bank accounts and car. A beneficiary designation may be all that young person needs. However, as people acquire more assets, especially when they buy homes or become the beneficiary of a trust, they will need more detailed planning.  And when you have a child, you need to have the hard conversation about who would be a proper guardian for your child if you were to pass away, and how you would want your estate administered for that child.