Software tools to support programmers and maintainers have been touted as potential solutions to the software development and maintenance crisis. Use of these tools is predicted to increase programmer productivity while simultaneously increasing the quality of the resulting software. Unfortunately, programmer use of these tools is lower than expected. We investigate maintenance programmers' choices about using software tools for their maintenance tasks using tasktechnology fit and fitness-for-use models. Our results indicate that the fit between maintenance tool functionality and the needs of maintenance tasks is associated with tool use. Two related factors, however, have stronger effects. First, the results are stronger for intention to use than for actual use. Specifically, while higher fit between tool and task is highly associated with intention to use, this intention may not lead to actual use. Second, maintainers' control over their environment affects usage. The more control maintenance programmers have over their resources and opportunities to use tools, the more likely they are to choose to use them. These results should concern maintenance managers who have acquired or are acquiring tools to increase productivity and quality, but are not realizing the benefits of their technology investments.