Thin film deposition systems are famously long-lived. With proper maintenance, instruments can last for decades! That said, with the ever-advancing march of technology, most systems eventually fall short of demands for higher throughput or improved yield. When that occurs, the deposition system will generally require a major overhaul in order to accommodate new modes of automation and advanced computer controls. When upgrades are not possible or feasible, it may be time to replace the entire system. The primary concern during such a change is maintaining consistency of performance between the old and new systems. It is imperative that films produced from the new deposition tool match that of the previous tool.