This study employed a qualitative research design to investigate how instructional designers use evaluation in everyday design practice. While past research has examined how designers spend their time, how they generally make decisions, and expert-novice differences, little attention has been paid to use of context, input, process, or product evaluation, from the perspective of practicing designers. Based on interviews of practitioners, our findings included ten themes regarding how designers use evaluation to improve their products. While these results substantiate to some degree the claim that practitioners believe clients will not pay for formal evaluations, they also suggest that practitioners use evaluation in important but less formal ways. Other conclusions regarding the role of evaluation in design are provided and future directions for training and research are discussed.