CMOS is furthermore the most widespread technology for digital designs as no feasible alternative is in sight to date and in the near future. The fundamental causes for this supremacy so far are the capability for miniaturization as well as the reliability and robustness of CMOS. Against the background of nanotechnology though, reliability concerns are arising with an alarming pace. The consequence is an increasing demand for approaches to improve both yield and lifetime reliability of today's complex integrated systems. Hence, a common solution is the redundant implementation of components. However, redundancy contradicts those other efforts in order to cope with power dissipation. Thus, the essential contribution of this work is an approach that increases the lifetime reliability of integrated circuits while delay and power penalties are kept to a minimum. Accordingly, "Sleep Transistors" (as a common technique to reduce standby leakage) are combined with the idea of modular redundancy. Furthermore, we propose an extended flow for the quantification of reliability on transistor level. Finally, the presented simulation results evidence that the suggested approach increases the lifetime reliability by more than a factor of two compared to initial designs.