Firstly, if your children are under 18, it is important to write a will so that you can have a say in who would look after them if you and any co-parents or guardians were to die. If you and any co-parent or guardian were to die the court will appoint guardians, which might not reflect your wishes. Secondly, it allows you to provide for them, either directly if the child is over the 18, or through a trust, for children under 18. Lastly, sorting your Will allows you to give particular items you own to your children, ranging from practical gifts like a car to sentimental ones.