Recent advances in web survey methodology were motivated by the observation that respondents increasingly use mobile devices, such as smartphones and tablets, to participate in web surveys. Even though we do not doubt this general observation, we argue that the claim is lacking a solid empirical basis. Most research on increasing mobile device use in web surveys covers limited periods of time and/or analyzes data from only one study or panel. There is a surprising lack of comprehensive overviews on the magnitude of mobile device use in web surveys. In the present study, we explored this research gap by analyzing data from 128 web surveys collected in four different academic studies in Germany between 2012 and 2020. Overall, we found strong empirical evidence for an increase in smartphone use, a stagnation in tablet use, and a decrease in desktop PC use. There was no evidence that the increase in smartphone use will slow down any time soon. Thus, we recommend that survey researchers prepare for a device change in web surveys that may enable new applications in web surveys.