The rapid growth in the range of data measures from wearable and stationary sensing devices has led to the adoption of multiple devices in health research. Such multi-device setups present challenges in sustaining patient engagement to capture continuous and high-quality datasets. One approach is to present health data to patients throughout the study but often occurs upon study completion. We report on preliminary insights from a feasibility study (IDEA-FAST) where multiple devices were used by 141 patients in their free-living environments. Interviews with a subset of patients and clinicians highlight challenges and opportunities around participation, data use and interpretation, including understanding compliance and data explainability with patients. We propose that summarising metadata from device usage could foster engagement and scale across a range of technologies regardless of the specific measures or post-processing algorithms provided by devices.