Periodic condition monitoring systems for reciprocating compressors have successfully provided cylinder pressure and other measurements on reciprocating compressors for many years. Cylinder pressure measurements alone enable diagnostic tools such as pressure versus volume (PV) curves to derive the condition of the sealing elements inside the cylinder. Reciprocating compressor continuous monitoring systems with acceleration and cylinder pressure measurement capabilities have gained commercial acceptance for improving compressor reliability. These systems consist of a variety of transducers, electronic protection/data collection hardware and data analysis and trending software. The transducers are permanently attached to the compressor and the data collection hardware installed at the compressor. Combining the cylinder pressure, rod load and crosshead pin, piston rod to crosshead connection, and piston to piston rod as well as cylinder condition. Suncor Energy required such a system on critical reciprocating compressors to improve their compressor valve monitoring and maintenance and reliability practices. This paper presents a short tutorial of the systems installed at Suncor Energy in Commerce City, Colorado and case histories that demonstrate the benefits experienced by Suncor. Suncor Energy was able to 1) detect a valve design flaw and correct it, 2) move from typical preventative maintenance practices to more reliability center predictive maintenance practices, and 3) detect valve failures early and avoid excessive downtown that cost upwards of $1M/day.