Sometimes it is not reasonably possible for a person to discover the cause of an injury, or even to know that an injury has occurred, until considerably after the act which causes the injury. For example, an error in the drafting of a will might not be noticed until the will is being executed, decades after it was drafted, or a financial planner's embezzlement might not be noticed for years due to the issuance of false statements of account.
When it applies, the "discovery rule" permits a suit to be filed within a certain period of time after the injury is discovered, or reasonably should have been discovered. The discovery rule does not apply to all civil injuries, and sometimes the period of time for bringing a claim post-discovery can be short, so it is important to seek legal assistance quickly in the event of the late discovery of an injury.