The financial implications of long-term restoration projects for cultural heritage, as compared to regular maintenance efforts, often underscore a flawed decision-making process. This can result from years of neglect versus consistent, organized maintenance. Striking a balance between these strategies is paramount for preserving cultural legacies. This research aims to evaluate the trade-offs between the initial expenditures of restoration initiatives and the consistent costs of maintenance activities. We leverage Building Information Modelling (BIM) and its specialized application for heritage preservation, known as Heritage Building Information Modelling (HBIM). This offers a digital depiction of the heritage building’s conservation state and associated intervention costs. Specifically, this study taps into the fifth dimension of BIM, cost estimation, to draw a comparative analysis between the financial ramifications of regular maintenance and long-term restoration projects. This assessment is exemplified through a case study on the “Aidkeen Al-Bendqdari Dome” located in historic Cairo, Egypt—a component of the Prince Taz Palace. The analysis integrates cost data to generate insights. The ultimate goal is to devise a comparative framework that can guide authorities in budgetary decisions and resource distribution.