A characteristic feature of the innovation process is the uncertainty with the term of efficient use of the new product. The article proposes the use of the "modified internal rate of return" indicator for determining the period of implementation of aninnovative project. The application of the present recommendations contributes to anincreased objectivity while making important managerial decisions related to setting an optimal duration of innovation use, planning the efficiency value of the employed capital, comparing alternative innovative projects, and also predicting the need for further development of innovations or their complete replacement by more progressive ones.