How might we describe ‘states of use’ for technology (AT)? In the AT field, uptake of or adherence to assistive products and the opposite state, abandonment of assistive products, are considered key outcome metrics. In this paper, two occupational therapists practicing and researching in very different contexts reflect upon definitions of assistive technology ‘use’. This iterative method firstly draws together definitions sourced from the various literature reviews informing i) a study recently completed in the Faroe Islands, and ii) a study currently underway in Australia. The two study methods are then presented and contrasted. The results demonstrate the ways in which operational definitions of use and non-use influence data analysis. The discussion considers the international directives which can assist practitioners and researchers to use consistent and meaningful definitions to more fully understand AT use, underuse and non-use. In conclusion, delivering on WHO UNICEF Global Report on AT Recommendation 6 Invest in data and evidence based policy requires comparable evidence and is supported by studies designed according to agreed definitions and standardized terminology.