工程的驗收程序代表著定作人受領工作之意思表示，一旦驗收通過，即會發生受領工作之法律上效果，包括報酬請求權之時效開始進行、逾期違約金之計算終止、保固期間之開始計算等效力。然而，並非每項工作都可以順利進入驗收程序，當定作人與承攬人就完工的認定不同或定作人有意拖延驗收程序時，對承攬人行使報酬請求權即會產生妨礙，因此工作是否完成之認定必須要能兼顧承攬人報酬請求權之產生及行使。在工作完成而無法進入驗收程序的情形時，勢必要另有認定工作完成的時點，在英美法上係以實質完工的理論來認定工作之完成及報酬請求權產生的時點。因此驗收程序的縱使有所拖延，亦不會影響報酬請求權之發生。其次，在尚未完成驗收程序即先行使用時，亦容易產生問題。在英美法上，雖然先行占用本身不構成對工作之受領，但在工程已達實質完工階段，並由定作人先行占有使用時，即應認為定作人已受領，並發生保固期間開始起算等效力。此外，報酬請求權之產生與瑕疵擔保請求權之關係為何，在實務上亦時有爭議。在工作已達實質完工但仍有瑕疵之情況下，究應為工作不完成而不得請求報酬，抑或工作已完成而僅得主張瑕疵擔保責任此點雖有爭議，但在瑕疵僅屬細微之情形下，仍宜認為報酬請求權已發生，僅餘瑕疵擔保責任之問題而己。

The procedures of inspection and acceptance of a work, the decision-making processes of the acceptance of a work by the owner, is of great significance in a construction project. Once the acceptance of work has been made through these procedures, the legal effect of recognition of the work, including the limitation period of compensation claims and the running of warranties commence and the calculation of liquidated damages ceases. However, not every work can smoothly enter to the procedures of inspection and acceptance. Contractors and owners often dispute when the project is complete, which frequently result in the withholding of formal acceptance by owner. Secondly, owners sometimes take possession of the sites and use the work before accepting the work, other important issues will be brought that whether the owner accept the work and when the period of warranties commence? In summary, the purpose of this article is to explore the relationship between the completion of works and the entitlements of the contractors under construction contracts. In exploring this issue, this article looks at the definition and the determination of the completion, including formal completion and substantial completion and the legal effect of completion of works at first. Determining the end of the contract performance period often generates many disputes. The owner wants everything done by the stated date while the contractor wants to get off the job and get paid. A theory to balance the interests between them is substantial completion, which helps to determine the completion of work and prevent the delay of payment by owners. Substantial completion generally occurs when the owner receives what is has bargained for and can occupy and use the project for its intended purpose. Typically the contractor is entitled to recover the contract price minus the cost of remedying minor defects at that time. Secondly, acceptance of a work is of great significance and generally limits the owner’s ability to complain of obvious defects and reject the works. Once a work has reached the stage of substantial completion and the owner has declined to accept it, it should be dealt with by the theory of constructive acceptance. In common law, the theory of constructive acceptance has evolved to help contractors avoid the harsh consequence of the unreasonable withholding of formal acceptance. Generally final acceptance requires final completion and final payment. However, under certain circumstances “constructive” acceptance can occur where the owner utilizes an area of the project and acts without objection to any of the contractor’s performance. Lastly, the practical completion of the works should not be certified in the event that there are patent defects in the work. It is a basic principle of common law that when a contractor undertakes to do work for a fixed sum, he is not due any payment until the whole of the work has been completed. If he can not get the certification of substantial completion, he will not be entitled of the payment. The determination of completion is effected by the extent of the defects. What the difference between completion of work with defects and non-completion is also be an interesting issue and deserved to be discussed.