Computer-Aided Software Engineering (CASE) tools have been advocated for improving maintainer productivity and the quality of maintained software. While there is evidence that such benefits can accrue to organizations adopting maintenance-oriented CASE tools, a key problem in achieving the desired benefits from CASE tools is low usage of these tools by programmers. The previously tested Maintenance Tool Utilization Model was a first step in investigating the factors that affect whether maintainers choose to use CASE tools during maintenance projects. We test the addition of experience with software maintenance tools and with the software maintenance task to the Maintenance Tool Utilization Model. The role of experience is important because managers can provide training to increase experience and they can ensure that project teams have some members experienced with the tools or with the task. Data for the test are collected from software maintainers working on their organization’s normal maintenance project backlog. Tool experience is significant as both a main and interaction effect, but task experience adds little to the explanatory power of the Maintenance Tool Utilization Model. These results support the value of improved CASE tool training programs.