cases do not need to be resolved within the period specified in the statute of limitations. Purpose The purpose and effect of statutes of limitations are to protect defendants. There are three reasons for their enactment: A plaintiff with a valid cause of action should pursue it with reasonable diligence. By the time a stale claim is litigated, a defendant might have lost evidence necessary to disprove the claim. Litigation of a long-dormant claim may result in more cruelty than justice. In Classical Athens, a five-year statute of limitations was established for almost all cases, exceptions being such as the prosecution of non-constitutional laws (which had no limitation). Demosthenes wrote that these statutes of limitations were adopted to control "sycophants" (professional accusers). The limitation period generally begins when the plaintiff's cause of action accrues, meaning the date upon which the plaintiff is first able to maintain the cause of action in court, or when the plaintiff first becomes aware of a previous injury (for example, occupational lung diseases such as asbestosis). Statute of repose A statute of repose limits the time within which an action may be brought based upon when a particular event occurred (such as the completion of construction of a building or the date of purchase of manufactured goods), and does not permit extensions. A statute of limitations is similar to a statute of repose, but may be extended for a variety of reasons (such as the minority of the victim). For example, most U.S. jurisdictions have passed statutes of repose for construction defects. If a person receives an electric shock due to a wiring defect that resulted from the builder's negligence during construction of a building, the builder is potentially liable for damages if the suit is brought within the time period defined by the statute, normally starting with the date that construction is substantially completed. After the statutory time period has passed, without regard to the nature or degree of the builder's negligence or misconduct, the statute of repose presents an absolute defense to the claim. Statutes of repose are sometimes controversial; manufacturers contend that they are necessary to avoid unfair litigation and encourage consumers to maintain their property. Alternatively, consumer advocates argue that they reduce incentives to manufacture durable products and disproportionately affect the poor, because manufacturers will have less incentive to ensure low-cost or "bargain" products are manufactured to exacting safety standards. Tolling