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 Tacoma home near the water, the main upkeep is rinsing the salt film off the cables and posts so the stainless keeps its finish. There is none of the staining, sealing, or repainting a wood baluster railing demands, which matters on a salt-air exposed deck.