## 2 Materials and Methods  
### Participants  
A total of 36 participants were recruited and interviewed: 24 patients and 12 care partners. Although there are no established criteria for recruiting participants for qualitative studies, studies show that it is common to recruit between 1 and 30 participants for in-depth interviews [53]. Furthermore, we found that data saturation can be achieved with 12 participants [54]. Considering these suggestions, we decided to recruit 12 participants from each of the three geographically different locations in the United States to account for variability that might exist among the three locations. This resulted in a total number of 36 participants that were equally recruited among the study locations with eight patients and four care partners from each location. The participants were recruited from three dialysis centers within the Veterans Affairs (VA) Health Care System in the United States. The centers were located in Seattle, WA; Louisville, KY; and Nashville, TN. At each location, we partnered with a local research coordinator who approached potential participants while they were either receiving dialysis treatment as a patient or accompanying someone receiving dialysis treatment as a care partner. The research coordinators approached individuals and identified them as potential participants by first asking them if they were at the dialysis center to receive dialysis treatment as a patient or accompanying a patient as a care partner. At this screening step of the recruitment process, the research coordinators ensured that patients and care partnerswere not recruited as dyads but instead as individuals. Then, the research coordinators used a diversity recruiting matrix that considered participants' age, gender, and race. We required that the care partners did not provide care for the patients enrolled in this study. Instead, the care partners should be providing care to other patients with kidney disease. The care partners should also not have kidney diseases requiring dialysis themselves. This was to avoid the possibility that the patients and their care partners might provide similar responses during the interviews, thereby inducing bias. Our decision to recruit patients and care partners individually and not as dyads was further guided by the goal of our study; to explore individual expectations rather than shared experiences, and to optimize data diversity with respect to our research constraints [55]. During our recruitment process, the participants were informed of the goal of the study and given the opportunity to ask questions they might have regarding their study commitment. Prior to participation, the participants were asked to provide informed consent and informed that at any given time throughout the study period, they had the opportunity to forgo their participation. Each patient successfully recruited was added to the recruitment matrix. At the end of the study, each participant was provided with a 30 U.S. dollar cash card as compensation for their participation. Such study compensation may help relieve participants of their financial sacrifices, acknowledge participants' contributions to medical sciences, and accelerate the process of reaching the optimal number of study participants [56]. Table 1 shows the characteristics of the study participants. The participants were between the ages of 45 and 86 years old, with a mean age of 65.08 years (SD = 8.82). Of the participants, 25 identified as male, and 11 identified as female. In terms of ethnic demographics, 18 identified as Black (50%), 11 as White (31%), and 7 as Other (e.g., Asian, Hispanic; 19%), and most of our participants indicated their highest level of education to be a high school degree. We also gathered participants' familiarity with mobile medical devices where the participants scored a median of 2 on a scale from 1 to 5, where 1 indicates being \"very unfamiliar\" and 5 indicates being \"very familiar\" with using mobile medical devices.