This exploratory study investigates the program comprehension strategies employed during enhancement and corrective maintenance from the perspective of the programmer activities of examining both program and task documentation and analysing and potentially modifying program code. Twenty-nine experienced C programmers independently undertook one of two maintenance tasks on the same C program and their various activities were recorded. Analysis and comparisons of activity durations were conducted at various points during the maintenance task as well as at the level of the complete task. The results show that contrary to previous research in this area, programmers implementing a correction utilized program documentation and header information significantly more than programmers undertaking an enhancement. Within their projects, this comparative additional usage occurred predominantly in the second quarter of the project suggesting more pronounced domain modeling than enhancers. Enhancers themselves made much more specific use of task documentation than did corrective programmers, seemingly to map out extensions and adjustments to their program models and, finally, to verify the code modifications made.