Challenging a will is a very tough task. It is important to note that most wills pass through without any contests, and even the ones that are contested are unlikely to be changed. Judges are unwilling to alter the last wishes of a deceased person unless clear evidence supports the claims of the people challenging the will.
Having said all of that, it is not impossible to challenge a will, and if you fell you were wrongfully cheated out of assets or benefits that you believe you deserve, then challenging a will is certainly a legal option for you. There are a few circumstances and conditions that can make for a legitimate and successful challenge to a will.
- Testamentary capacity. If the grantor did not have the testamentary capacity to make critical decisions (i.e. if he or she has dementia) then they may have botched the value of an asset or given assets to beneficiaries who don't necessarily "deserve" it in your eyes.
- Fraud or forgery. These should be obvious, but if a will was forged or a beneficiary committed fraud to bolster his or her prospects when the estate was executed, then there would be grounds for a challenge.
- Undue influence. These circumstances occur when someone applies pressure to a grantor to change his or her will when the grantor may not be in the best condition to make these decisions. In a way, it blends in with testamentary capacity.
Source: FindLaw, "Reasons to Challenge a Will," Accessed Nov. 3, 2016