Choosing and changing the model of trial mode is one of the most relevant and widely discussed tasks for many software developers. It is easy to make a model for some programs and difficult for others. And some people are haunted by the question: "Have we made everything right?" The task of choosing a trial-model is relevant to us, PVS-Studio developers, as well. We decided to share some of our ideas regarding this subject and tell you about a new alternative we have invented. We hope that our arguments and some ideas will be helpful to other developers too.