Unlike many eighteenth-century clockmakers, Jean-Jacques Fiéffé never became a wealthy man. Despite holding an important position within his guild, his fortune was modest, and his workshop contained only three clocks when he retired. His work was highly regarded by his contemporaries, as Fiéffé's clock movements were usually installed in cases of very high quality, made by well-known craftsmen. He used the title Clockmaker of the [Paris] Observatory, which probably meant that he was responsible for maintaining that building's clocks. Fiéffé retired early, after the death of his wife in 1758. He was succeeded by five sons, four of whom became master clockmakers like their father.