Introduction: This article provides a summary of findings from French data regarding the predictive value of daily living independence for the onset of dementia. Methods: The findings presented are drawn from the Paquid cohort and its 27-year follow-up, which allowed for the exploration, in an initial sample of 3,777 older adults, of functional manifestations during the long pre-dementia phase. A clinical diagnosis of dementia was made at each follow-up time point, and the Instrumental Activities of Daily Living (IADL) scale was used to assess early functional manifestations, particularly using the scores for the four most cognitively demanding IADLs (telephone, transportation, budgeting, and medication management). Results: Various studies confirm the presence of functional manifestations several years before the onset of dementia and highlight the strong predictive value of IADLs for the development of new-onset dementia. However, differences exist based on gender, educational level, or the risk period considered (short-term versus long-term). Conclusion: Difficulties in daily life, sometimes mild, manifest several years before diagnosis. A simple and rapid indicator such as the score on the 4 IADLs would be useful in clinical practice to identify individuals at highest risk of developing dementia and for whom monitoring of cognitive and functional changes over time is necessary, in order to implement appropriate care when the time comes.