In this article, I discuss the categories of time and space in light of heritage preservation. I demonstrate that heritage creation is simultaneously the creation of human time and space and that critical treatment of heritage requires a more specific analysis of these terms. Although change is central to the conservation theory, it is also a concept that raises the greatest doubts and ambiguous interpretations. The reason for this is very simple: change is related to as foundational a concept as time. In this article, I use metaphysical time models to analyse the life course of things, their damage, and in the end I also refer to conservation theories derived from Eugène Viollet-le-Duc and John Ruskin. The essential difference between the conservation theories discussed here lies in their attitudes toward time, and the related problems of object authenticity and identity. In the framework of the presentist model, it is not possible to solve the main contradiction connected to restoration. Stylistic restoration ruined the authenticity of buildings as historic documents; however without restoration, the objects would have been destroyed and thereby also lost their historic value. However, it is possible to find a solution to this dilemma based on the eternalist time model, which helps connect heritage to contemporary time, and avoid its physical, legal, and mental separation from everyday life of society. The fact that considering objects as part of heritage could damage them instead of preserving them should also not be overlooked. The authenticity of an object is not related to any ideal state in its history but to a conceptual, factual and actual state in its wholeness.