The researches carried out in the relics of the history of architecture and urban planning of Iran in the field of architectural studies and urban planning have been more closely related to the body of these relics. In the meantime, social factors, cultural, religious and customary structures and the opinion of the master craftsman, architect or even the king and the courtiers have been neglected in the form of regulations, despite their undeniable effect. It seems that Iran's architecture has principles based on which architects have acted in relation to durability and long useful life of buildings. The creation of desirable and high-quality architectural works that have the capacity to last and adapt to life and the passage of time has been happening in Iran for a long time. This article seeks to answer the question of whether the regulations related to architecture during the Qajar era until the constitution were involved in increasing the lifespan and quality of the  relics, or did they take steps to reduce it? This study has been carried out in the context of a part of history, from the time of the rule of the Qajar kings to the emergence of constitutionalism. In this era, with the emergence of the first forms of urban organization, regulations play a more prominent role than in the past. In this article, the data collected and analyzed systematically during the research process have been used. Based on this method, first open coding is done up to the stage of theoretical saturation, and then classification and analysis of the codes is done up to the stage of selective codes. The purpose of compiling this article is to first read the documents belonging to the mentioned period and extract the existing regulations at that time and then measure its effect on increasing or decreasing the useful life of architectural  relics. Therefore, firstly, the regulations related to architectural constructions or urban spaces from the Qajar era to the Constitution have been summarized and then the relationship between these factors and the useful life of the building has been investigated. According to the nature of the Qajar period and the emergence of factors that reduced the lifespan and quality of architecture, the classification has been separated into two general categories: increase and decrease in durability.