The Canadian Study of Health and Aging was a large, multidisciplinary, national core study--with a number of "add-on" investigations--of the epidemiology of dementia and the health of older people. This structure was a fiscally prudent way to balance between mandated and investigator-initiated inquiry. In hindsight, several important features of the study would be repeated. Future studies might profitably consider a longer funding period for analysis, and a more strategic approach to in-depth, supplementary studies.