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For centuries, lighthouse keeping demanded round-the-clock vigilance, as keepers manually lit lamps, wound clockwork mechanisms that rotated the lens, and polished glass to prevent light diffusion caused by soot or salt residue. Isolation was a defining feature of the profession; many stations, particularly those on remote rock outcrops, could only be resupplied by boat during calm weather, leaving keepers cut off for weeks during storms. The introduction of electric lighting reduced some manual labor, but keepers still monitored fog signals and logged weather conditions meticulously, since accurate records aided both navigation and eventual automation planning. By the late twentieth century, most lighthouses had been converted to automated, remotely monitored systems, rendering the resident keeper largely obsolete, though a small number of stations retain staff for historical or ceremonial purposes.