Maintaining large software systems based on Commercial Off-The-Shelf (COTS) components is a major cost driver for these systems. Maintenance includes activities from component replacement to trouble-shooting and configuration management. The maintenance costs for COTS based software systems can be reduced by building systems according to specific design criteria. This paper identifies the major activities of a system maintainer, describes the properties that can be designed into a system to facilitate these activities, and outlines a checklist of items that can be verified during a design or code review, or during the evaluation of a COTS components in order to guarantee these properties are built into the system. The verification is illustrated using a photo imaging system that is currently under development.