All buildings have a service life. In order to extend this service life as much as possible in order to preserve the functionality but also the safety of the use of the building, maintenance measures must be implemented. Building maintenance is the sum of all activities that monitor the condition and seek to preserve the purpose of the building for which it was designed. Since all phases in the life of a building take the longest duration, this makes the costs of using and maintaining the buildings the highest costs, and should be considered for a reduction already in the design phase. In recent years, there has been an awareness of the importance of these costs and their consideration, which is the mission of this work. The problem of maintenance should be viewed in terms of the overall construction process, because meeting the needs for construction facilities involves the permeation of construction activities such as: construction of new buildings, modernization and replacement of existing ones, and maintenance.This paper explains the maintenance of buildings, the goals of maintenance, the life cycle of a building with an emphasis on the phase of use and maintenance, and all the costs that occur when maintaining the building. The example of a public-purpose building in Osijek was used as a model for designing and presenting a maintenance plan based on an analysis of the present values of the costs of use and maintenance. A maintenance plan for a period of forty years (from 2019 to 2059) has been developed that includes preventative and reactive maintenance activities. A sensitivity analysis was also made to make the impact of the change in the discount rate and the analysis period on the total costs visible, which is necessary for better risk management in that period.