As computer based training devices proliferate, the need to maintain the software associated with the devices will cease to be an isolated need and will become a general requirement. Based on experience with tactical systems, it can be estimated that the maintenance of the software associated with a simulator over the life of the device will cost at least as much as the original acquisition cost of the software. In this paper the procedures and requirements for software maintenance are analyzed. The many associated trade-offs are examined. Based on the requirements of post deployment support the impact on the acquisition process is examined. Recommendations are made as to how the acquisition or development phase can best support post deployment support activities for software such that system utility can be maximized and life cycle costs minimized.