This paper introduces reliability centered software testing as a methodology for analysis, planning and control of the test factors affecting the reliability of software prior to the software release. These main factors are: resources and time-to-software-release. These two factors are interdependent, allowing you to determine whether to increase the applied resources and shorten TTSR or to reduce resources and extend TTSR. This paper argues that you can significantly improve the results of software quality testing by optimizing the test duration. This involves varying the rate of the above two factors (resources and TTSR) and using the appropriate failure intensity models. This paper, based on hands-on experience, presents a methodology for planning the trade-off between resources and TTSR by controlling testing phase duration. In the process, we attempt to define the most typical pitfalls in planning testing phase duration, i.e. TTSR, and offer some practical recommendations on how to avoid these pitfalls. Following this procedure, you will be able to select the ETSR level that is best suited to achieving the goal of releasing your software on time, while assuring its predetermined reliability level.