No an attorney is not needed but if at all possible it is better to have a lawyer help you with your will.  There are several legal requirements in Iowa law that a person must follow regarding creating their will.  If some of these requirements are not met then the probate court may be forced to disregard your will and give out your assets as if you had no will.  Your will is the only way to force others to carry out your wishes after you die so it is worth it to have a lawyer to ensure that the will is valid.