amp; Zacher, 2021) have been raised, as they often emphasise after-hours work communication and checking behaviours, potentially limiting content validity. We propose a new scale to capture a broader range of TASW behaviours, which may help clarify mixed findings in prior research. Method. We conducted 25 in-depth interviews with employees from Czechia, Austria, and the United Kingdom, identifying six themes through thematic analysis: communication, checking behaviour, unfinished tasks, work preparation, and knowledge expansion. This informed a preliminary scale, which we refined through several pilot studies. We then collected data from a Czech national panel (N = 2000) to assess reliability and validity, followed by an experience sampling study to examine the scale’s characteristics over short time frames. Results and conclusions. Data analysis is in progress. We perform a factor analysis and examine the interplay between general, daily, and momentary TASW assessments. We also study the interrelations between TASW and digital wellbeing, recovery experience, segmentation norm and preference, basic psychological needs satisfaction, work overload. We expect to disentangle positive and negative TASW effects with daily and momentary assessment. Results and conclusions will be finalised in time for the congress. Further studies will expand this research to German- and English-speaking countries.