With the increasing offer of fertility treatment by a largely privatised sector, which has involved the proliferation of treatment add-ons lacking evidence of effectiveness, In-Vitro Fertilisation (IVF) patients are expected to make informed choices on what to include in their treatment. Drawing on interviews with 51 individuals undergoing fertility treatment, this article explores patients' approaches to medical evidence interpretation and its role in their decisions to include add-ons. While most IVF patients share understandings of what counts as medical evidence, our findings show how their approaches also differ. Our analysis focuses on how patients negotiate the notion of medical evidence and its relation to other forms of experience or knowledge. We present four different (1) delegating evaluations of evidence to experts; (2) critically assessing available evidence; (3) acknowledging the process of making evidence; and (4) contextualising evidence in their lived experience of infertility. We suggest that patients' choice to include add-ons is not due to a lack of information on or understanding of evidence, but rather should be interpreted as part of the complexity of patients' experiences of infertility.