Through the panel study of twelve Montrealers from 1971 to 1995, this article examines the variation between the conditional and the imperfect morphology in hypothetical si-clauses. The two variants, well in place in the spoken French implicit norms system, are in opposition when given values in the normative debate. The analysis indicates the influence of the distance and the event potentiality. Due to vacillations in usage frequency according to the year, the study cannot confirm the hypothesis of a change in favor of the conditional morphology. This case study documents the individual variation across the lifespan and its connection to community change.