You might like this article, especially this part…
There are a couple of misconceptions about how often the Bridge is painted. Some say once every seven years, others say from end to end each year. The truth is that the Bridge is painted continuously. Painting the Bridge is an ongoing task and a primary maintenance job. The paint applied to the Bridge’s steel protects it from the high salt content in the air which can cause the steel to corrode or rust.
Golden Gate Bridge