Very little. Stainless cable railings need an occasional wipe-down and a periodic check of the cable tension, and quality hardware tensioned correctly at install holds for years. On a Cle Elum home, including a vacation property that sits empty through the winter, that low upkeep is a real advantage, since there is nothing to seal or repaint between visits the way there is with a wood baluster railing. A wipe-down when you are up keeps the stainless bright.