Longitudinal research is a powerful tool. By following groups of people across time, we can track how things change, or stay the same, in their lives. The Centre for Longitudinal Studies (CLS) houses four of the UK’s national longitudinal cohort studies, tracking the lives of tens of thousands of people. Each of the four studies follows large, nationally representative groups of people born in a given year. Increasingly, we have turned to new technologies and methodological innovations for a multitude of purposes for the cohort studies. This talk will cover some of the opportunities and challenges associated with the use of wearable technology and biomeasure collection in a longitudinal context, illustrated by our experiences on the CLS cohort studies.