Operators generally want to reduce well down-time and repair/replacement costs by improving the reliability of their Artificial lift (AL) systems. In order to understand if actions taken to improve reliability are effective, one must track the AL system run-life. This paper discusses run-life measures commonly used in the AL industry and provides recommendations for when each run-life measure should be used. Synthetic data, generated using random runtime and failure data from known statistical distributions, is used to illustrate the effect of various factors, such as selecting equipment with higher inherent reliability, on the resulting measured run-life. This paper also presents several pitfalls that should be avoided when selecting run-life measures for comparing equipment or implementing operator-vendor alliance contracts.