Valuable estates can easily become war zones. The desire for land, possessions, or other assets can quickly sever family ties. Estates are typically distributed per the wishes of the deceased. But not always. There are cases when a court determines legitimate grounds exist to question a will’s validity. These contests, however, can trigger the beginning of a never-ending, bitter family feud. They are costly legal actions that take years to resolve. Three common grounds used to contest a will, include:

1. Ignoring Formalities

Probate rules often require a declaration by the testator of the signing of a will, two witnesses, and signatures by all. Formalities were ignored in the case of Thomas Kinkade, Painter of Light, who died in California in 2012. After his death, his new girlfriend produced two handwritten wills that stated Kinkade was leaving her his home, $10 million dollars, and a share in Kinkade’s continuing legacy. Handwritten wills are valid in approximately half of the states, and California is one of them. Kinkade’s wife of 30 years, mother of his four children, battled the girlfriend in court. A confidential agreement was later agreed to after months of litigation.

2. Lack of Capacity

Testators must be of sound mind when signing a will. John Seward Johnson, I, son of the founder of Johnson & Johnson, was worth $400 million when he died in 1983. His will gave his estate to his third wife. His six children contested the will on the grounds that he was incompetent. The court determined that the children would receive six million dollars each. In the end, the wife kept the majority of the estate, and the children were left with a legal bill of $25 million.

3. Undue Influence

Ernie Banks, of the Chicago Cubs, composed a new will three months before he died, giving control of his estate to his caregiver. Those not included in the will were Banks’ estranged wife, and sons. The family claims that the caregiver took advantage of Banks’ declining health, and separated him from his family, while the caregiver insists Banks purposefully left the relatives out. Two years after the athlete’s death, the two sides are still at odds.

Even with legitimate grounds, contested wills are expensive, and time consuming. When a substantial amount of money is involved, the wise, plan ahead, and plan carefully.