Studying at university places high demands on the control and regulation of one's own learning behavior. In order to support students' learning, we developed and used a webtool containing elements such as regular performance testing as well as feedback on test performance and self-evaluations. In this report, we first introduce core elements of the applied webtool. Then, we present findings on student's use of this tool. Results show substantial variability in willingness and frequency of tool usage between students. Students with better final school exam grades and students who intended to engage regularly in course postprocessing were more willing to use such a tool. The findings are discussed against the background of regulation requirements in open learning environments and implications on better implementation are derived.