This article presents the theoretical and practical evolution of a study (1994-1999) on long-term unemployment for older workers. Considering as standing point the problematic of exclusion, the authors have progressively matured towards a problematic of reflexivity. Today, they submit the different analysis approaches structuring the relationship between work and ageing, and then situate the evolution of their conceptual approach, which shifts from system to actor subject, and the notions of social experience and reflexivity. A few case study results illustrate the evolution of this process.