The problem of creep and long-term strength of metallic materials and alloys is considered. It is proposed to determine the damage parameter changes from experimental high-temperature creep curves. In this case, only one kinetic equation for the creep rate for the case of a compressible medium is formulated. The continuity parameter is determined from this kinetic equation and depends on the creep rate and creep deformation. Similarly, the changes in the continuity parameter are determined by the Rabotnov solution. For the case of a compressible medium, a more intense accumulation of damage and, correspondingly, fracture processes is observed, compared with the Rabotnov solution.