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 may include mobility trackers, sleep trackers, brain MRIs, stool collection, and additional memory tests for participants who visit Data Collection Sites. In addition, new or expanded questionnaires have been added on quality of life, sleep, nutrition, healthcare use, sexual health and family history of disease for all CLSA participants.