In short: Copper gutters that have been installed properly, with attention to infrequent, but regular maintenance, can last for 60-90 years. Possibly as long as a century. Copper gutters are a natural and sensible complement to any natural roof, but especially slate. A beautiful stone roof is made more lovely with well-made copper gutters. They frame the edge of the roof, drawing the eye upward, bringing attention to the layers of slate, copper flashing, and other embellishments.
Commercial gutter installers frequently mistreat copper as though it were aluminum, ignoring its unique thermal properties. Copper will swell and contract as it heats and cools, more so than aluminum or steel. Without the proper placement of expansion joints – seams in the metal that give room for the metal to move – the copper can apply considerable force as it swells, fracturing itself. Moreover, an amateur installer might use caulk or caulk hidden behind a copper cover to seal joints. Caulk obviously won’t last as long as the copper, requiring frequent touch ups and related repairs. For these and countless other reasons, an experienced hand is key when working with copper.