Previous research on open-ended questions revealed several factors influencing the answers provided by respondents in web surveys. Among others, motivating instructions have proven to elicit long and rich responses. Furthermore the visual design of the answer box size influences the answers provided by respondents. Small boxes seem to pose a lower response burden and therefore reduce itemnonresponse. Larger answer boxes increase burden but at the same time motivate respondents to provide more extended responses. Based on this evidence finding the ideal box size seems to require a trade-off balancing item-nonresponse and the length of the answers. Web surveys offer opportunities to deal with this dilemma and optimize answers to open-ended questions. In a survey among the university freshman students we conducted experiments using auto-adjusting answer boxes. Moreover, we used the amount of information respondents typed into the first open-ended question to assign them later in the survey a custom-size answer box. Results suggest that the web survey specific enhancement in the visual design of text boxes influences data quality. Especially the adaptive assignment of answer boxes reduce item-nonresponse for those respondents who did not answer in the first place while prolific writers typed more detailed answers into the second box. Results are discussed in light of the general question whether questionnaire design in general and visual design in particular should be used to instruct respondents on how to answer an question or whether an adaptive design should be used that adjusts elements of the questionnaire to the behavior of respondents.