Approaches to harmonization of methods for determining the optimal level of investment in the renewal of the fleet of combine harvesters and current expenses of agricultural enterprises under conditions of implementation of sustainable development goals in the activities of economic entities are investigated. It is established that the implementation of the concept of sustainable development for the domestic agricultural sector intensifies the processes in it, brings to the fore the problems of ensuring food security of the State, increasing the production of safe products while preserving landscapes and minimizing anthropogenic pressure. At the same time, the seizure of part of the territory, mining of the liberated and adjacent to the combat zone areas raises the issue of rational use of land resources. Under such conditions, only further introduction of innovations aimed at increasing yields and the use of intensive technologies is the most important vector for the development of domestic agriculture. This places strict requirements on the technical condition of its resource potential. Unfortunately, the unsatisfactory technical condition of the grain harvesting machinery fleet and its destruction as a result of hostilities exacerbate the problem of technical support for grain production, in particular for harvesting. Under such conditions, an important task is to develop methodological techniques for determining the optimal, harmonized values of investments in the reproduction of resource potential and operating costs. The tested methodological approach allows determining the optimal level of investment in the renovation of the combine harvester fleet, taking into account the peculiarities of wheat production organization, grain price conditions, material resources, harvesting equipment, and financial factors. The calculations showed that it is economically inexpedient to invest in the renewal of the combine harvester fleet using the most common combine harvester models if one unit has less than 600 hectares of wheat crops. A positive feature of the tested approach is the ability to minimize unproductive costs by taking into account technological and market factors in determining the optimal level of costs. Instead, the introduction of innovations leads to a change in the form of the production function, which should affect the dynamics of the marginal efficiency of investments, and therefore it is promising to expand approaches to modeling and take into account the role of innovations in finding the optimal level of current costs and investments.