There are several points throughout a person's life when it may be a good idea to update an estate plan. A person who turns 18 should, at minimum, have powers of attorney that name people to make healthcare decisions and take over finances if the person is incapacitated by illness or injury.
Most people revise the estate plan when they get married. The plan may need another revision if they have a child. The estate plan might need to name the surviving spouse as the full beneficiary. Otherwise, minor children may inherit a portion of the estate. The surviving spouse might then have to go to court and get approval as a guardian to manage the children's inheritance until they turn 18. An estate plan should also name a guardian for minor children in case both parents die at the same time.