Approximate computing techniques based on Voltage Over-Scaling (VOS) can provide quadratic improvements in power efficiency. However, voltage scaling is limited by the inherent fault-tolerance of an application, thus preventing VOS schemes from realizing their full potential. To gain further power efficiency a reduction of the error rate experienced in a given voltage level is required. We propose Lazy Pipelines, a micro-architectural technique that utilizes vacant cycles in a VOS functional unit to extend execution and reduce the error rate.