Writing is an important aspect of experimental physics. Physics laboratory classes typically engage students in scientific documentation and writing in the forms of lab notebooks, reports, or proposals. Instructors of these classes may have a variety of motivations for incorporating writing. We previously developed a framework for thinking about the role of writing in physics lab classes that lists and categorizes possible goals instructors may have for writing. Here, we use that framework as a research tool to investigate students' views about, and experiences with, writing in lab classes, and experimental physics more generally. We present results of an analysis of student responses to weekly reflection questions throughout one semester of an advanced lab class. The results suggest that students think about writing in a variety of ways, and that the context and framing of the course may impact student thinking about the purpose of writing.