Programmers are encouraged to comment their source programs, yet the value of the comments is not easily verified. In this study, the relationships between comment quantity and software metrics are assessed to determine whether programmers increase comment quantity in complex modules. In addition, comment quantity and software metrics are related to software maintenance data. It was found that software complexity, as measured by software metrics, accounts for a substantial portion of the variance in comment quantity. Additionally, comment quantity has no statistically significant relationship to software maintainability for the task studied.