At each interview, you will be asked questions about your health and well-being, including physical, social and emotional functioning, lifestyle and behaviours, as well as the onset of health conditions and diseases. Most of the questions you answer will be repeated across follow-ups. This allows researchers to assess how the health and well-being of participants change over time. Additional questions or tests are introduced in each follow-up, to ensure the CLSA is gathering the most comprehensive data. For example, new data collection measures introduced in Follow-up 3 includes mobility trackers, sleep trackers, brain MRIs, stool collection, and additional memory tests.